Estimated radiation risk of cancer from dental cone-beam computed tomography imaging in orthodontics patients

Accuracy of Magnetic Resonance Imaging in Clinical Endodontic Applications: A Systematic Review

INTRODUCTION

The development of dedicated coils and new magnetic resonance imaging (MRI) sequences has led to an increase in image resolution and a reduction in artifacts. Consequently, numerous studies have demonstrated the utility of MRI as a nonionizing alternative to cone-beam computed tomographic imaging. The aim of this systematic review was to evaluate the accuracy of MRI in clinical applications in endodontics.

METHODS

A literature search was conducted using PubMed, Embase, Scopus, and Web of Science. The inclusion criteria encompassed studies evaluating MRI applications in endodontics, covering tooth and root canal anatomy, root canal working length, pulp vitality and regeneration, the effect of caries on dental pulp, guided endodontics, periapical lesions, and root cracks/fractures. The selected studies examined both ex vivo and in vivo human teeth using clinical MRI units. Two researchers independently screened the studies, applied the eligibility criteria, and assessed the potential risk of bias using the revised QUADAS-2 tool (Bristol Medical School, University of Bristol, UK).

RESULTS

A total of 18 studies were included in this systematic review, demonstrating that the use of MRI has a high diagnostic value in endodontics. In the evaluation of tooth and root canal anatomy, pulp vitality and regeneration, the effect of caries on dental pulp, periapical lesions, and root cracks/fractures, MRI's accuracy is comparable to or even higher than reference standards such as cone-beam computed tomographic imaging, micro-computed tomographic imaging, and histology.

CONCLUSIONS

MRI has high potential accuracy for diagnosing various clinical endodontic tasks, except for root canal length, size of caries, and periapical lesion dimensions, which are overestimated in MRI.

The use of CBCT in orthodontics with special focus on upper airway analysis in patients with sleep-disordered breathing

Applications of cone-beam CT (CBCT) in orthodontics have been increasingly discussed and evaluated in science and practice over the last two decades. The present work provides a comprehensive summary of current consolidated practice guidelines, cutting-edge innovative applications, and future outlooks about potential use of CBCT in orthodontics with a special focus on upper airway analysis in patients with sleep-disordered breathing. The present scoping review reveals that clinical applications of CBCT in orthodontics are broadly supported by evidence for the diagnosis of dental anomalies, temporomandibular joint disorders, and craniofacial malformations. On the other hand, CBCT imaging for upper airway analysis-including soft tissue diagnosis and airway morphology-needs further validation in order to provide better understanding regarding which diagnostic questions it can be expected to answer. Internationally recognized guidelines for CBCT use in orthodontics are existent, and similar ones should be developed to provide clear indications about the appropriate use of CBCT for upper airway assessment, including a list of specific clinical questions justifying its prescription.

The effect of optimum, indication-specific imaging fields on the radiation exposure from CBCT examinations of impacted maxillary canines and mandibular third molars

OBJECTIVE

Indication-specific optimum field-of-views (FOVs) have been assessed for CBCT scans of impacted maxillary canines and mandibular third molars, as 40∅ × 35 mm and 35∅ × 35 mm, respectively. The objective was to investigate possible changes in absorbed organs and effective doses, for these two imaging indications, performing CBCT examinations with optimum FOV sizes instead of commonly used FOVs. Additionally, radiation exposure-induced cancer risk was calculated for both imaging indications with optimum FOVs.

METHODS

An adult female head phantom (ATOM 702-D, CIRS, Norfolk, VA, USA) was scanned using Planmeca Viso G7 CBCT-device (Planmeca, Helsinki, Finland). Scanning factors, different FOV sizes, dose-area product (DAP) values and anatomical FOV locations were used for Monte Carlo PCXMC-simulation and ImpactMC software. In the PCXMC- simulation, 10-year-old child and 30-year-old adult phantoms were used to estimating effective and absorbed organ doses.

RESULTS

The effective dose varied from 58 µSv to 284 µSv for impacted maxillary canines, and from 38 µSv to 122 µSv for mandibular third molars, the lowest dose value for each corresponding to optimum FOV. Effective dose reduction between the optimum FOV and the smallest common FOV of 50∅ × 50 mm, maintaining other scanning factors constant, was 33% for impacted maxillary canines, and 45% for mandibular third molars. At all examinations, the highest absorbed organ doses were in salivary glands or in oral mucosa.

CONCLUSIONS

Optimum FOVs, 40∅ × 35 mm for impacted maxillary canine and 35∅ × 35 mm for mandibular third molar, could decrease effective doses received by young patients, and improve radiation safety in these common CBCT imaging procedures.

Clinical and medico-legal considerations in endodontics

Endodontic treatment can be challenging for a number of reasons, including the microscopic nature of the clinical environment, reliance on tactile sensation and lack of direct visualization of the work being performed. Commonly, endodontic patients present with pain and distress, which can exacerbate an already difficult clinical situation. Complications may might arise prior to, or during treatment, despite practising with the utmost care and skill. Preventing and managing these complications can take considerable time and energy, and oftentimes assistance from or referral to more experienced colleagues is required. The aim of this review is to discuss medico-legal considerations in endodontics, with clinical correlations and a focus on the Australian legal landscape. [Correction added on 18 October 2023, after first online publication: The abstract was amended from a structured to an unstructured abstract.].

Dental MRI-only a future vision or standard of care? A literature review on current indications and applications of MRI in dentistry

MRI is increasingly used as a diagnostic tool for visualising the dentoalveolar complex. A comprehensive review of the current indications and applications of MRI in the dental specialities of orthodontics (I), endodontics (II), prosthodontics (III), periodontics (IV), and oral surgery (V), pediatric dentistry (VI), operative dentistry is still missing and is therefore provided by the present work.The current literature on dental MRI shows that it is used for cephalometry in orthodontics and dentofacial orthopaedics, detection of dental pulp inflammation, characterisation of periapical and marginal periodontal pathologies of teeth, caries detection, and identification of the inferior alveolar nerve, impacted teeth and dentofacial anatomy for dental implant planning, respectively. Specific protocols regarding the miniature anatomy of the dentofacial complex, the presence of hard tissues, and foreign body restorations are used along with dedicated coils for the improved image quality of the facial skull.Dental MRI poses a clinically useful radiation-free imaging tool for visualising the dentoalveolar complex across dental specialities when respecting the indications and limitations.

Cone-beam computed tomography use in postgraduate orthodontic programs in North America and Europe

OBJECTIVES

Cone-beam computed tomography (CBCT) has emerged over recent decades as a rapid acquisition technology that allows practitioners to view the craniofacial complex in high spatial detail. This study aimed to assess the latest trend of CBCT use in postgraduate orthodontic programs in North America and Europe/Australia.

METHODS

An electronic multiple-choice survey was sent via email requesting anonymous participation of postgraduate orthodontic program directors: 73 in North America (as listed on the American Association of Orthodontists website) and 189 in Europe/Australia (as listed on the European Orthodontic Society website). Survey collection was over a 2-month period with two follow-up emails sent 2 weeks and 1 month after the initial email to each program director who had not responded. Responses were collected directly on Qualtrics for analysis.

RESULTS

The response rate was 46.6% (34 responses) for North America and 11.1% (21 responses) for Europe/Australia. Results revealed that 100% of respondents from North America had access to a CBCT scanner, while 90.48% of respondents (19 responses) from Europe/Australia had access. Most North American postgraduate orthodontic programs have CBCT scanners within their clinic, while most European/Australian programs do not, and they refer patients to the radiology department. Although there is a higher percentage of programs in North America compared to Europe/Australia that use CBCT as part of routine orthodontic records for all patients, most programs in both regions use CBCT imaging for specific diagnostic purposes and not for routine records.

CONCLUSION

Overall, North American programs have more access to CBCT scanners in postgraduate clinics and use CBCT imaging more routinely than European/Australian programs.

[Radiation dose permitted in dentistry patients. A review]

In dental practice, the use of imaging has increased over the years, generating an increase in the radiation dose for the dental patient. One factor under discussion is the amount of dose used in patients, men, women and children, at different stages of their life, due to the scientific evidence of the harmful effects of ionizing radiation. This review of the literature analyzed the characteristics of radiation and its effects in relation to the doses administered, and its equivalences in dental practice in panoramic periapical radiographs and cone beam tomographies. A search of the literature was carried out in the main information sources such as Medline (via PubMed), SEVIER, SCIELO, and LILACS, using the search terms with a date limitation of the last 10 years. The selected articles had to include information regarding the keywords used, including "Dental Offices, Radiation Dose, X-Rays, Ambulatory Care."

Endodontic working length measurements of premolars and molars in high-resolution dental MRI: a clinical pilot study for assessment of reliability and accuracy

OBJECTIVES

To prospectively assess the reliability and accuracy of high-resolution, dental MRI (dMRI) for endodontic working length (WL) measurements of premolars and molars under clinical conditions.

MATERIALS AND METHODS

Three-Tesla dMRI was performed in 9 subjects who also had undergone cone-beam computed tomography (CBCT) (mean age: 47 ± 13.5 years). A total of 34 root canals from 12 molars (4/8, upper/lower jaw; 22 root canals) and 11 premolars (2/9 upper/lower jaw; 12 root canals) were included. CBCT and dMRI datasets were reconstructed to visualize the root canal in one single slice. Subsequently, two radiologists measured the root canal lengths in both modalities twice in blinded fashion. Reliability and accuracy for both modalities were assessed using intraclass correlation coefficients (ICCs) and Bland-Altman analysis, respectively.

RESULTS

Reliability (intra-rater I/II; inter-rater) of dental MRI measurements was excellent and comparable to CBCT for premolars (0.993/0.900; 0.958 vs. 0.993/0.956; 0.951) and for molars (0.978/0.995; 0.986 vs. 0.992/0.996; 0.989). Bland-Altman analysis revealed a mean underestimation/bias (95% confidence interval) of dMRI measurements of 0.8 (- 1.44/3.05) mm for premolars and 0.4 (- 1.55/2.39) mm for molars. In up to 59% of the cases, the accuracy of dMRI for WL measurements was within the underestimation margin of 0 to 2 mm short of the apical foramen AF.

CONCLUSIONS

In vivo demonstration and measurement of WL are feasible using dMRI. The reliability of measurements is high and equivalent to CBCT. Nonetheless, due to lower spatial resolution and longer acquisition time, the accuracy of dMRI is inferior to CBCT, impeding its current use for clinical treatment planning.

CLINICAL RELEVANCE

dMRI is a promising radiation-free imaging technique. Its reliability for endodontic working length measurements is high, but its accuracy is not satisfactory enough yet.

Impact of thyroid gland shielding on radiation doses in dental cone beam computed tomography with small and medium fields of view

OBJECTIVE

The purpose of this study was to evaluate the impact of thyroid gland shielding on radiation doses in dental cone beam computed tomography (CBCT) with small and medium fields of view (FOVs).

STUDY DESIGN

Six CBCT protocols were investigated by exposing an adult anthropomorphic male phantom head without and with thyroid shielding, using 4 small (4 × 5 cm) and 2 medium (10 × 6 cm) FOVs. Twenty metal oxide semiconductor field-effect transistor dosimeters were placed in the phantom head to measure absorbed doses and calculate equivalent doses at 11 sites. Effective doses were calculated based on the tissue weighting factors in International Commission on Radiological Protection Publication 103. The data were analyzed using the independent samples t test.

RESULTS

Thyroid gland shielding led to significant equivalent dose reductions in many tissues for all protocols. Equivalent dose reductions to the thyroid were significant in all 6 protocols (P ≤ .037). Significant reduction depended on the FOV and ranged between 24.5% and 42.6% for the thyroid gland and 4.9% and 34.5% for other tissues and organs. Effective doses were significantly lower in all protocols (P ≤ .016).

CONCLUSIONS

Thyroid gland shielding protects the thyroid gland and other organs and should be utilized with all CBCT examinations where feasible.

A Review of Doses for Dental Imaging in 2010-2020 and Development of a Web Dose Calculator

Dental imaging is one of the most common types of diagnostic radiological procedures in modern medicine. We introduce a comprehensive table of organ doses received by patients in dental imaging procedures extracted from literature and a new web application to visualize the summarized dose information. We analyzed articles, published after 2010, from PubMed on organ and effective doses delivered by dental imaging procedures, including intraoral radiography, panoramic radiography, and cone-beam computed tomography (CBCT), and summarized doses by dosimetry method, machine model, patient age, and technical parameters. Mean effective doses delivered by intraoral, 1.32 (0.60-2.56) μSv, and panoramic, 17.93 (3.47-75.00) μSv, procedures were found to be about1% and 15% of that delivered by CBCT, 121.09 (17.10-392.20) μSv, respectively. In CBCT imaging, child phantoms received about 29% more effective dose than the adult phantoms received. The effective dose of a large field of view (FOV) (>150 cm2) was about 1.6 times greater than that of a small FOV (<50 cm2). The maximum CBCT effective dose with a large FOV for children, 392.2 μSv, was about 13% of theeffective dose that a person receives on average every year from natural radiation, 3110 μSv. Monte Carlo simulations of representative cases of the three dental imaging procedures were then conducted to estimate and visualize the dose distribution within the head. The user-friendly interactive web application (available at http://dentaldose.org) receives user input, such as the number of intraoral radiographs taken, and displays total organ and effective doses, dose distribution maps, and a comparison with other medical and natural sources of radiation. The web dose calculator provides a practical resource for patients interested in understanding the radiation doses delivered by dental imaging procedures.

The Reliability of Two- and Three-Dimensional Cephalometric Measurements: A CBCT Study

Cephalometry is a standard diagnostic tool in orthodontic and orthognathic surgery fields. However, built-in magnification from the cephalometric machine produces double images from left- and right-side craniofacial structures on the film, which poses difficulty for accurate cephalometric tracing and measurements. The cone-beam computed tomography (CBCT) images not only allow three-dimensional (3D) analysis, but also enable the extraction of two-dimensional (2D) images without magnification. To evaluate the most reliable cephalometric analysis method, we extracted 2D lateral cephalometric images with and without magnification from twenty full-cranium CBCT datasets; images were extracted with magnification to mimic traditional lateral cephalograms. Cephalometric tracings were performed on the two types of extracted 2D lateral cephalograms and on the reconstructed 3D full cranium images by two examiners. The intra- and inter-examiner intraclass correlation coefficients (ICC) were compared between linear and angular parameters, as well as between CBCT datasets of adults and children. Our results showed that overall, tracing on 2D cephalometric images without magnification increased intra- and inter-examiner reliability, while 3D tracing reduced inter-examiner reliability. Angular parameters and children's images had the lowest inter- and intra-examiner ICCs compared with adult samples and linear parameters. In summary, using lateral cephalograms extracted from CBCT without magnification for tracing/analysis increased reliability. Special attention is needed when analyzing young patients' images and measuring angular parameters.

Thyroid Collars in Dental Radiology: 2021 Update

Background: In 2013, the American Thyroid Association (ATA) issued a "Policy Statement on Thyroid Shielding During Diagnostic Medical and Dental Radiology." The recently updated National Council on Radiation Protection and Measurement Radiation Protection in Dentistry and Oral and Maxillofacial Imaging (NCRP Report No. 177) prompts this review of progress related to patient thyroid shielding since the ATA statement was published. Summary: Relevant publications appearing since the ATA statement were identified by querying PubMed for "thyroid and dental and (collar or shielding)" and substituting specific dental radiographic procedures in the search. The search was expanded by reviewing the cited papers in the PubMed-retrieved papers and by use of the Web of Science to retrieve papers citing the PubMed retrieved publications. Although many quantitative studies have appeared reflective of current dental radiographic instrumentation and practice, much more can be done to foster minimizing radiation to the thyroid. Conclusions: We list seven areas that should be pursued. Among them are harmonizing guidelines for the use of thyroid collars based on the recent studies and a comprehensive survey of current dental radiological practice patterns.

Orthodontists' criteria for prescribing cone-beam computed tomography-a multi-country survey

OBJECTIVES

This study aimed to describe and compare CBCT imaging prescription in clinical practice among orthodontists from five countries in Europe and America. Additionally, it investigated factors associated with the prescribing and the use of guidelines for CBCT imaging.

MATERIALS AND METHODS

A cross-sectional survey was carried out using an online questionnaire sent to all registered orthodontists in Belgium, Brazil, Canada, Romania, and the United States of America (USA). The data were analyzed by descriptive statistics, bivariate tests, and Poisson regression.

RESULTS

The final sample consisted of 1284 participants. CBCT was prescribed by 84.4% of the participants for selected cases (84.9%), mainly for impacted teeth (92.4%), presurgical planning (54.1%), and root resorption (51.9%). High cost was most frequently the limiting factor for CBCT prescription (55.4%). Only 45.2% of those who were using CBCT imaging reported adhering to guidelines. CBCT imaging prescription was associated with the orthodontists' countries (p < .009, except for Belgium, p = .068), while the use of guidelines was associated with the respondents' country and additional training on CBCT imaging (p < .001).

CONCLUSIONS

Orthodontists refer patients for CBCT for selected indications (impacted teeth, root resorption, presurgical planning, dentofacial deformities, as suggested by the international guidelines, and also for upper airway and temporomandibular joint evaluation). Many do not adhere to specific guidelines. There are substantial variations between the countries about the orthodontists' referral for CBCT and guideline usage, irrespective of gender. CBCT prescription may be limited by financial barriers, adhering to specific guidelines and prior CBCT training.

CLINICAL RELEVANCE

CBCT prescription among orthodontists must be based on prescription criteria and current guidelines. It is advised to improve CBCT education and training to enhance CBCT selection, referral, analysis, and interpretation in orthodontic practice.

Projected lifetime cancer risk from cone-beam computed tomography for orthodontic treatment

Objective

To estimate the projected cancer risk attributable to diagnostic cone-beam computed tomography (CBCT) performed under different exposure settings for orthodontic purposes in children and adults.

Methods

We collected a list of CBCT machines and their specifications from 38 orthodontists. Organ doses were estimated using median and maximum exposure settings of 105 kVp/156.8 mAs and 130 kVp/200 mAs, respectively. The projected cancer risk attributable to CBCT procedures performed 1-3 times within 2 years was calculated for children (aged 5 and 10 years) and adult (aged 20, 30, and 40 years) male and female patients.

Results

For maximum exposure settings, the mean lifetime fractional ratio (LFR) was 14.28% for children and 0.91% for adults; this indicated that the risk to children was 16 times the risk to adults. For median exposure settings, the mean LFR was 5.25% and 0.58% for children and adults, respectively. The risk of cancer decreased with increasing age. For both median and maximum exposure settings, females showed a higher risk of cancer than did males in all age groups. Cancer risk increased with an increase in the frequency of CBCT procedures within a given period.

Conclusions

The projected dental CBCT-associated cancer risk spans over a wide range depending on the machine parameters and image acquisition settings. Children and female patients are at a higher risk of developing cancer associated with diagnostic CBCT. Therefore, the use of diagnostic CBCT should be justified, and protective measures should be taken to minimize the harmful biological effects of radiation.

Reconstruction of Panoramic Dental Images Through Bézier Function Optimization

Computed tomography (CT) and X-ray images have been extensively used as a valuable diagnostic tool in dentistry for surgical planning and treatment. Nowadays, dental cone beam CT has been extensively used in dental clinics. Therefore, it is possible to employ three-dimensional (3D) data from the CT to reconstruct a two-dimensional (2D) panoramic dental image that provides a longitudinal view of the mandibular region of the patient, avoiding an additional exposure to X-ray. In this work, we developed a new automatic method for reconstructing 2D panoramic images of the dental arch based on 3D CT images, using Bézier curves and optimization techniques. The proposed method was applied to five patients, some of them with missing teeth, and smooth panoramic images with good contrast were obtained.

Effect of CBCT dose reduction on the mandibular canal visibility: ex vivo comparative study

OBJECTIVES

To compare the difference in mandibular canal (MC) visibility using three different cone beam computed tomography (CBCT) acquisition protocols: high resolution (HR), standard resolution (ST) and Quick scan+ (QS+).

METHODS

Twenty-five human dry mandibles were scanned by one CBCT machine; i-CAT FLX (Imaging Sciences International, Hatfield, PA, USA), using three different acquisition protocols: high-resolution (HR), standard (ST) and Quick scan+ (QS+). DICOM data were transferred to a third party software Ondemand 3D (Cybermed Co., Seoul, Korea). The fusion module was used to superimpose images derived from different acquisition protocols to standardize the areas to compare the MC visibility. Comparison was performed at nine selected cross sections extending from an area distal to the third molar posteriorly to the first premolar anteriorly. Two expert radiologists evaluated the degree of MC visibility using five-scale scoring system.

RESULTS

There was a statistically significant difference between the three acquisition protocols (HR, ST, QS+) at all investigated areas regardless of dentition status (p value < 0.001-0.034) except at the MR1M area where there was no statistically significant difference (p value = 0.094). HR protocol showed the highest prevalence of fully and partially corticated MC at almost all investigated areas while QS+ protocol showed the highest prevalence of invisible MC and clear and unclear non-corticated MC at almost all investigated areas.

CONCLUSIONS

QS+ protocol of i-CAT FLX CBCT machine is a recommended low-dose CBCT acquisition protocol for MC visibility at dentulous posterior mandibular regions while ST protocol is recommended at edentulous areas.

Cone-beam computed tomography and its applications in dental and maxillofacial radiology

Cone-beam computed tomography (CBCT) was first used in dental and maxillofacial radiology (DMFR) at the end of the 1990s. Since then, it has been successfully established as the standard three-dimensional radiographic imaging technique in DMFR, with a wide variety of applications in this field. This manuscript briefly reviews the background information on the technology and summarises available data on effective dose and dose optimisation. In addition, typical clinical applications and indications of the technique in DMFR are presented.

Quantification of DNA Double Strand Breaks and Oxidation Response in Children and Adults Undergoing Dental CBCT Scan

Assessing the possible biological effects of exposure to low doses of ionizing radiation (IR) is one of the prime challenges in radiation protection, especially in medical imaging. Today, radiobiological data on cone beam CT (CBCT) related biological effects are scarce. In children and adults, the induction of DNA double strand breaks (DSBs) in buccal mucosa cells and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG) and antioxidant capacity in saliva samples after CBCT examination were examined. No DNA DSBs induction was observed in children nor adults. In children only, an increase in 8-oxo-dG levels was observed 30 minutes after CBCT. At the same time an increase in antioxidant capacity was observed in children, whereas a decrease was observed in adults. Our data indicate that children and adults react differently to IR doses associated with CBCT. Fully understanding these differences could lead to an optimal use of CBCT in different age categories as well as improved radiation protection guidelines.

Cone-Beam Computed Tomography in Orthodontics

Unlike patients receiving implants or endodontic treatment, most orthodontic patients are children who are particularly sensitive to ionizing radiation. Cone-beam computed tomography (CBCT) carries risks and benefits in orthodontics. The principal risks and limitations include ionizing radiation, the presence of artifacts, higher cost, limited accessibility, and the need for additional training. However, this imaging modality has several recognized indications in orthodontics, such as the assessment of impacted and ectopic teeth, assessment of pharyngeal airway, assessment of mini-implant sites, evaluation of craniofacial abnormalities, evaluation of sinus anatomy or pathology, evaluation of root resorption, evaluation of the cortical bone plate, and orthognathic surgery planning and evaluation. CBCT is particularly justified when it brings a benefit to the patient or changes the outcome of the treatment when compared with conventional imaging techniques. Therefore, CBCT should be considered for clinical orthodontics for selected patients. Prescription of CBCT requires judicious and sound clinical judgment. The central question of this narrative review article is: when does CBCT add value to the practice of orthodontics? To answer this question, this article presents discussion on radiation dosage of CBCT and other imaging techniques used in orthodontics, limitations of CBCT in orthodontics, justifying the use of CBCT in orthodontics, and the benefits and evidence-based indications of CBCT in orthodontics. This review summarizes the central themes and topics in the literature regarding CBCT in orthodontics and presents ten orthodontic cases in which CBCT proved to be valuable.

Utilização da imagem por ressonância magnética na odontologia: revisão de literatura

A Imagem por Ressonância Magnética (IRM) tem sido considerada a modalidade de escolha para o diagnóstico de processos patológicos que acometem a articulação temporomandibular, tecidos moles e outros processos inflamatórios. Devido a sua característica não invasiva e livre de radiação ionizante, novas aplicações para a técnica têm sido propostas e estudadas nas mais diversas áreas da Odontologia, como Endodontia, Dentística, Periodontia e Cirurgia Oral. O objetivo neste trabalho é apresentar uma revisão de literatura acerca da utilização da IRM na Odontologia, destacando as vantagens e limitações da técnica.

The accuracy and stability of the maxillary position after orthognathic surgery using a novel computer-aided surgical simulation system

Background

Many reports have been published on orthognathic surgery (OGS) using computer-aided surgical simulation (CASS). The purpose of this study was to evaluate the accuracy of the maxillary repositioning and the stability of the maxilla in patients who underwent OGS using a newly developed CASS program, a customized osteotomy guide, and a customized miniplate.

Methods

Thirteen patients who underwent OGS from 2015 to 2017 were included. All patients underwent a bimaxillary operation. First, a skull-dentition hybrid 3D image was rendered by merging the cone beam computed tomography (CBCT) images with the dentition scan file. After virtual surgery (VS) using the FaceGide® program, patient-customized osteotomy guides and miniplates were then fabricated and used in the actual operation. To compare the VS with the actual surgery and postoperative skeletal changes, each reference point marked on the image was compared before the operation (T0) and three days (T1), four months (T2), and a year (T3) after the operation, and with the VS (Tv). The differences between ΔTv (Tv-T0) and ΔT1 (T1-T0) were statistically compared using tooth-based reference points. The superimposed images of Tv and T1 were also investigated at eight bone-based reference points. The differences between the reference points of the bone surface were examined to evaluate the stability of the miniplate on the maxilla over time.

Results

None of the patients experienced complications. There were no significant differences between the reference points based on the cusp tip between ΔTv and ΔT1 (p > 0.01). Additionally, there were no significant differences between the Tv and T1 values of the bone surface (p > 0.01). The mean difference in the bone surface between Tv and T1 was 1.01 ± 0.3 mm. Regarding the stability of the miniplate, there were no significant differences between the groups. The difference in the bone surface between T1 and T3 was − 0.37 ± 0.29 mm.

Conclusions

VS was performed using the FaceGide® program, and customized materials produced based on the VS were applied in actual OGS. The maxilla was repositioned in almost the same manner as in the VSP plan, and the maxillary position remained stable for a year.