Assessment of cone-beam CT technical image quality indicators and radiation dose for optimal STL model used in visual surgical planning.

OBJECTIVES: The aim of this study was to identify cone-beam computed tomography (CBCT) protocols that offer an optimal balance between effective dose and 3D model for orthognathic virtual surgery planning, using CT as a reference, and to assess whether such protocols can be defined based on technical image quality metrics. METHODS: Eleven CBCT (VISO G7, Planmeca Oy, Helsinki, Finland) scan protocols were selected out of 32 candidate protocols, based on effective dose and technical image quality measurements. Next, an anthropomorphic RANDO SK150 phantom was scanned using these 11 CBCT protocols and 2 CT scanners for bone quantity assessments. The resulting DICOM files were converted into STL models that were used for bone volume and area measurements in the predefined orbital region to assess the validity of each CBCT protocol for VSP. RESULTS: The highest CBCT bone volume and area of the STL models were obtained using normal dose protocol (F2) and ULD protocol (J13) which resulted in 48% and 96% of the mean STL bone volume and 48% and 95% of the bone area measured on CT scanners, respectively. CONCLUSIONS: The optimal normal dose CBCT protocol" F2" offered optimal bone area and volume balance for STL. The optimal CBCT protocol can be defined exhibited similar using CNR and MTF values that were similar with of those of the reference CT scanners'. CBCT scanner with selected protocols can offer a viable alternative to CT scanners for acquiring STL models for VSP at a lower effective dose.

Skeletal stability after mandible bilateral sagittal split osteotomy - comparison of patient-specific implant and mini-plate fixation: A retrospective study.

The aim of the study was to compare the stability of the virtual surgical planning (VSP) and computer-aided design accompanied by patient-specific implants (PSIs) and conventional mini-plates in mandible advancement with bilateral sagittal split osteotomy (BSSO). This retrospective study evaluates the clinical and cephalometric records of 53 patients (12 male, 41 female) treated with BSSO in Helsinki University Hospital. Subjects were divided into two groups: VSP-PSI (21 patients: 4 male and 17 female; mean age 38 years, range 25-53 years); and conventional wafer-based repositioning with mini-plate fixation (32 patients: 8 male and 24 female; mean age 39 years, range 21-56 years). The effect of the amount and direction of the advancement on the stability was also analysed individually. The standardized lateral cephalometric radiographs in three time points were analysed to compare the groups. After surgery (T2), there were no differences between groups in cephalometric variables. During follow-up (T2-T3), the cephalometric variables in both Groups A and B were stable, so there was no difference in stability between the VSP-PSI and the conventional mini-plate groups. During follow-up, the mandibles rotated clockwise or counterclockwise, relapsed towards their original direction, and the changes were statistically significant (jaw relationship; p = 0.018, soft tissue profile; p = 0.025); when the advancement of mandible was >6 mm, the increase in gonial angle compared to mandibles advanced ≤6 mm was statistically significant (p = 0.03). VSP-PSI and conventional mini-plate fixation can be considered equally stable. Large advancements with counterclockwise rotation regardless of fixation method are more susceptible to relapse. VSP-PSI alone cannot solve the relapse-related concerns in mandible osteotomy.

The Frequency of Temporomandibular Disorders, Surgical Complications, and Self-Reported Mental Health Problems in Orthognathic Patients.

OBJECTIVE: To evaluate the frequency of signs and symptoms of temporomandibular disorders (TMD), surgical complications, and patient's self-reported mental health problems during orthognathic treatment. MATERIAL AND METHODS: The clinical records of 145 patients treated with orthognathic treatment were retrospectively studied. Variables regarding occlusal parameters, treatment duration, TMD symptoms, complications, and self-reported mental health status at time points of T0 (beginning of the treatment), T1 (before surgery), and T2 (final examination) were evaluated. The variables were statistically compared with significance level of P < 0.05. RESULTS: A total of 51% (n = 74) of the patients had TMD symptoms at 1 or several time points, women having significantly more TMD signs and symptoms ( P = 0.002). Temporomandibular disorder signs and symptoms decreased significantly after orthognathic treatment ( P <0.001). At least 1 self-reported mental health-related factor during 1 or several time points (T0-T2) was recorded in 17.2% (n = 25) of the patients. There was no significant difference in frequency of self-reported mental health problems in patients with TMD signs and symptoms compared with patients without TMD signs and symptoms ( P > 0.05). The frequency of postoperative complications was 39.3%, being significantly higher after Bilateral Sagittal Split Osteothomy (BSSO, 48.7%). There was no difference in treatment duration of patients with self-reported mental health problems compared with patients without ( P > 0.05). CONCLUSIONS: In this study population, TMD signs and symptoms seem to be typical both in patients with or without self-reported mental health problems. Women had significantly more TMD symptoms. Orthognathic surgery treatment seems to have a positive effect on TMD signs and symptoms.

Surgical Treatment of Cherubism With the Use of ThreeDimensional Virtual Planning and CAD-CAM Resection Guides: A Case Report and Systematic Literature Review.

ABSTRACT: We report the use of a three-dimensional virtual surgical planning technique including both fusion and superimposition to obtain harmony and symmetry of the face in an 18-year-old woman suffering from cherubism. The treatment contained several threedimensional techniques that allowed precise planning and a predictable surgical outcome. The reduction plasty was successful, and the postoperative healing was uneventful. No relapse of the disease occurred after the surgical treatment and the sensation of the mentalis area recovered. The patient was satisfied with the aesthetic result and no additional surgery was needed. The surgical planning techniques described, and the CAD/CAM patient-specific resection guides seems to be safe and reliable in a one-step surgical treatment of cherubism patients after the disease has clearly ceased based on radiological findings. A systematic review of the literature on surgical correction of deformities due to cherubism was conducted. The systematic review of the existing literature was performed on the available studies from PubMed and Ovid Medline published before June 9, 2020. The search term was ''Cherubism.'' The inclusion criteria were: 1) full article published in English and 2) the patient had surgical treatment. We excluded the cases that included only minor surgery as biopsy or only treatment of unerupted teeth. The database identified 638 citations of which 50 met the eligibility criteria. The systematic review revealed no earlier use of surgical 3D planning in the treatment of cherubism.

Virtual Surgical Planning Combined With Intraoperative Navigation in Mandibular Bilateral Sagittal Split Osteotomy for Accurate Placement of Patient Specific Implants.

ABSTRACT: The aim of the study is to evaluate clinical methods to obtain a significantly improved fitting of patient specific implants (PSI) in bilateral sagittal split osteotomies and to evaluate the use of electromagnetic navigation as a potential guide for condyle positioning. A prospective study using (1) a solid bite registration index during preoperative computed tomography, (2) critical planning with regard to the condylar rotation, (3) a piezoelectric saw throughout the mandibular osteotomy, and (4) intraoperative navigation to determine the position of the PSIs and the mandibular segments intraoperatively was performed. Ten patients were treated. Five underwent bilateral sagittal split osteotomies and 5 bimaxillary osteotomy. All of the PSIs fitted precisely onto the mandible and the screws into the predrilled screw holes. The predetermined occlusion was obtained. A precise fitting of the PSIs in the lower jaw seems to be possible to achieve with above-mentioned methods. The intraoperative navigation system gives a possibility to verify the surgical outcome during surgery but is not accurate enough to be used as a virtual drill guide alone.

CAD/CAM Engineered Patient-Specific Impants as a Reposition Device in Le Fort I and Modified Subcondylar Osteotomies: Case Report of Facial Deformity Correction in Acromegaly.

Acromegaly is a medical condition where elevated growth hormone or insulin-like growth factor I levels cause several changes in the craniofacial soft and hard features. We report the correction of facial deformity and posterior open bite with Le Fort I and modified subcondylar osteotomies in a patient affected by acromegaly. Computer-aided design and manufacturing generated saw and drill guides were used to perform osteotomies and segment removal. The placement of the patient-specific implants (PSIs) was guided by predesigned drill holes ensuring the required and planned movement of the jaws and position of the PSIs. After segment removal, the PSIs fitted the predesigned drill holes with high precision and were secured without problems. The planned amount of mandibular and maxillary movement was achieved. The occlusion and osteotomies remained stable for the follow-up of 22 months. The use of PSIs combined with guided surgery can be beneficial for selected cases with asymmetry or posterior open bite enabling new approaches and yielding good functional and aesthetic outcome. The modification of conventional ramus osteotomy combined with utilization of ramus segment removal and the use of PSI for reposition is an interesting and promising technique for rare conditions with ramus height asymmetry.

No differences in infections between patient-specific implants and conventional mini-plates in mandibular bilateral sagittal split osteotomy - Up to 3-year follow-up.

The use of individually designed osteotomies, combined with individually manufactured osteosynthesis material, is rapidly becoming a standard for more challenging maxillofacial surgery. The benefits of patient-specific implants (PSI) in orthognathic surgery are clear in complex cases. PSIs can enhance precision and ease up the surgical protocol. We previously reported on the benefits of PSIs as reposition and fixation systems during Le Fort I osteotomy. The aim of this study was to evaluate a cohort of 28 patients, treated with bilateral sagittal split osteotomy (BSSO) and PSIs for fixation, with regard to healing for up to 3 years. A retrospective cohort of 48 patients with conventional mini-plate repositioned mandibles was also collected for statistical analysis. No statistically significant differences were found with regard to infection, soft tissue problems, or reoperations between these two groups.

Comparison of postoperative skeletal stability of maxillary segments after Le Fort I osteotomy, using patient-specific implant versus mini-plate fixation.

BACKGROUND: Three-dimensionally (3D) designed osteotomies and customised osteosynthesis are rapidly becoming standard in maxillofacial reconstructive and deformity surgery. Patient-specific implants (PSIs) have been in use for a few years in orthognathic surgery as well. In Le Fort I osteotomy, wafer-free fixation of the maxillary segment can be performed by individually manufactured cutting and drill guides together with PSIs. AIM: This retrospective study was performed to compare the postoperative skeletal stability of the maxillary segment fixed by patient-specific implants versus mini-plates after Le Fort I osteotomy. PATIENTS: Fifty-one patients were divided into subgroups according to the fixation method and the advancement of the sub-spinal point. The postoperative skeletal stability of the maxillary segment was evaluated from lateral cephalometric radiographs one year postoperatively. RESULTS: No statistically significant differences were found between the postoperative skeletal stability of the PSI and mini-plate fixed maxillae. Prospective studies, possibly with 3D fusion analysis, are warranted to confirm the results. CONCLUSION: The choice between the two fixation methods does not seem to affect the postoperative skeletal stability of the maxillary segments.

Comparison between patient specific implants and conventional mini-plates in Le Fort I osteotomy with regard to infections: No differences in up to 3-year follow-up.

Individually designed osteotomies and milled or printed patient-specific osteosynthesis materials are rapidly becoming a standard in maxillofacial reconstructive surgery. The benefits of using patient-specific implants (PSIs) in orthognathic surgery are especially clear in complex cases, and for this reason they are rapidly becoming common practice. We have earlier reported the benefits related to the use of PSIs as reposition and fixation system in Le Fort I osteotomy. The aim of this study was to compare complications associated with fixation with PSIs (31 patients) versus conventional mini-plates (37 patients) in Le Fort I osteotomy. No statistically significant differences in infection, reoperations or soft tissue problems were observed between the two systems used. Interestingly, three of the 37 patients in the mini-plate group underwent reoperation due to insufficient advancement or malocclusion, whereas none of the patients in the PSI group needed reoperation. In conclusion, PSIs are reliable for use in orthognathic surgery, with no signs of infection associated complications.

Surgical Treatment of Dentofacial Deformities Caused by Juvenile Idiopathic Arthritis.

The purpose of our retrospective study was to evaluate the results of orthognathic treatment, distraction osteogenesis, and/or prosthetic reconstruction of the temporomandibular joints in patients with juvenile idiopathic arthritis (JIA).Twelve patients with severely affected temporomandibular joints (TMJs) and reduced ramus height were treated with mandibular advancement with orthognathic surgery (11) and additional bilateral or unilateral mandibular ramus distraction (3) or additional bilateral or unilateral prosthetic reconstruction of the TMJ (3). One patient was treated surgically with bilateral TMJ prosthetic reconstruction only. The patients were followed up clinically and radiologically with emphasis on healing, TMJ function, stability of the occlusion, skeletal stability, and facial appearance for an average of 2.3 years after the final surgery. The mean mandibular advancement was 10.1 mm. The mean relapse at pogonion was 2.1 mm, which represents 20.8% of the surgical advancement. The occlusion was stable in 11/12 patients. The TMJ function was good and the facial esthetics improved in all patients. Orthognathic treatment and mandibular ramus distraction osteogenesis provide beneficial lengthening of the mandibular body in JIA patients with asymptomatic and stabile condyles. In adult patients with relapse of the disease or postoperative condylar relapse prosthetic total joint replacement is a reliable and safe alternative.

Osteotomy Site Grafting in Bilateral Sagittal Split Surgery With Bioactive Glass S53P4 for Skeletal Stability.

In orthognathic surgery, the aim of the treatment is to achieve a good occlusion and a satisfying aesthetic outcome. In large mandibular advancements insufficient healing at the mandibular inferior border may lead to loss of support for the overlaying tissue at the osteotomy site. Augmentation can be performed to improve stability, bone regeneration, and the aesthetic outcome. The purpose of this prospective clinical study was to evaluate the use of a novel material for this indication; granules of the antibacterial, osteoconductive, and slowly resorbing bioactive glass S53P4 as filling material in large mandibular advancement in bilateral sagittal split osteotomies. The authors treated 25 patients who underwent bilateral sagittal split osteotomies due to class II dentoskeletal deformities. The mandibular osteotomy site defects (8-15 mm) were augmented with bioactive glass S53P4. The average clinical follow-up was 33 months and the average radiological follow-up with cone beam computerized tomography was 24 months. The clinical and radiological results were good with regard to healing, bone regeneration, and stability of the osteotomy sites. The recontouring of the inferior mandibular border provided a good soft tissue support followed by an excellent aesthetic outcome in 96% of the osteotomy sites. The occlusion was stable in 88% of the patients. The authors' results show that bioactive glass S53P4 is a safe grafting material for osteotomy site defects in significant mandibular advancements with reliable bone regeneration, providing long-term stability at the osteotomy site and at the inferior mandibular border.

Craniofacial and Dental Features in Six Children With Cherubism.

Cherubism is an autosomal-dominant benign bone disorder, characterized by fibro-osseous lesions in the mandible and maxilla commonly caused by mutations in the SH3-binding protein 2-gene. The purpose of the authors' study was to analyze craniofacial and dental features of children diagnosed with cherubism, describe their treatment, and assess their dental age compared with norms for Finnish children. Six children were diagnosed, followed up and treated due to dental and skeletal disorders caused by cherubsim. The patients were followed up for an average of 91.5 months with emphasis on the skeletal changes and development of dentition. The treatment consisted of minor orthodontic treatment, dental extractions, and exposures. One patient underwent cosmetic mandibular surgery. All patients had lesions in the lower jaw and 5 of 6 patients had lesions in the maxilla as well. The patients were characterized by varying swelling of the jaws, premature loss of deciduous teeth in the affected area and widely spaced, displaced, un-erupted, or absent permanent teeth. The dental age was delayed at younger age but near to normal or even a little ahead at older age. Even though cherubism affects the jaws, jaw positions, and malocclusion, no common dentofacial proportions associated with the disease could be confirmed by cephalometric analysis. The surgical interventions did not provoke adverse reactions or local growth of the lesions.

Regeneration of Cystic Bone Cavities and Bone Defects With Bioactive Glass S53P4 in the Upper and Lower Jaws.

Cysts and tumors are common lesions in the jaws. To be able to retain a good volume of the alveolar ridge during healing as well as strengthening the angle and body of the mandible and provide an instant improved support for adjacent teeth, reliable long-term bone regeneration is needed. The purpose of this prospective study was to promote bone regeneration by filling bony defects in the upper or lower jaw with granules of the bioactive glass S53P4 (BAG), which have osteostimulative and antimicrobial properties.The authors treated 20 patients (21 defects) surgically; benign tumors, cysts, or infection related to impacted teeth in the maxilla or mandible. The tumor or cyst was removed or enucleated and thorough cleaning of the infected area was performed. The bone cavity was filled with granules of the BAG S53P4 despite signs of chronic infection in the area at the time of surgery. The patients were followed up for an average of 34 months clinically and with cone beam computerized tomography for 28 months. In 20 defects the final outcome was successful. Despite infection at the time of surgery in 65% of the patients, no material associated infection was seen during the follow-up. The BAG S53P4 granules were radiologically remodeled into bone after 2 years follow-up. The use of granules of the BAG S53P4 in the treatment of large bone defects provides infection-free reliable bone regeneration despite chronic infection at the time of surgery, which improves the prognosis of adjacent teeth.

The use of patient-specific implants in orthognathic surgery: A series of 30 mandible sagittal split osteotomy patients.

PURPOSE: Virtual surgery combined with patient-specific saw and drill guides and osteosynthesis materials are rapidly spreading from reconstructive surgery to orthognathic surgery. Most commercial partners are already providing computer-aided design and computer-aided manufacture (CAD/CAM) wafers and patient-specific saw guides. Clear benefits have been demonstrated for custom-made drill guides combined with individually designed three-dimensional (3D) printed patient-specific implants (PSI) as a reposition and fixation system in Le Fort I osteotomy. MATERIALS AND METHODS: We treated 30 patients who underwent bilateral sagittal split osteotomy (BSSO) due to class II dento-skeletal deformities with the additional use of drill guides combined with PSI as a fixation and positioning system. RESULTS: The PSIs fitted bilaterally with total precision in 11 of the 30 patients. In 17 patients, the PSIs were used with some modifications. In 2 of 30 patients, the PSIs could not be used as a fixation due to misfit. CONCLUSION: Due to unpredictable fitting, the use of PSIs with drill guides alone in BSSO without wafers cannot be recommended. Further studies are needed to evaluate the interfering parts, which seem to be related to condylar positioning and bony interferences at the osteotomy sites.

Rapid prototyped patient specific guiding implants in critical mandibular reconstruction.

Large tumours of the mandible need immediate reconstruction to provide continuity of the mandible, satisfactory function of the jaw, as well as an acceptable aesthetic outcome. In this prospective study we described the immediate reconstruction of the mandible using computer aided design and 15 rapid prototyped patient specific implants (PSI) in 14 patients suffering from benign or malignant tumours demanding continuity resection of the mandible. The scaffold PSI was filled with ß-tricalcium phosphate granules and autologous bone. Microvascular reconstruction was additionally needed in 12/15 cases. The clinical follow up was on average 33 months and the radiological follow up was on average 21 months. In nine cases the healing was uneventful. One patient lost the microvascular flap during the first postoperative week and one patient needed a revision due to perforation of the mucosa at the site of the PSI. Four patients had a major complication due to perforation of the mucosa leading to infection, which resulted in the total or partial removal of the PSI. The PSI seems to be a promising solution for treatment of patients demanding large reconstruction after mandible resection. The benefits are decreased rate of donor site complications and more accurate and prompt surgical procedure.

The use of patient-specific implants in orthognathic surgery: A series of 32 maxillary osteotomy patients.

The use of virtual surgery, patient-specific saw and drill guides, and custom-made osteosynthesis plates is rapidly spreading from deformity surgery to orthognathic surgery. Most of the commercially available systems are using computer-aided design/computer-aided manufacture (CAD/CAM) wafers to produce patient-specific saw guides. However, most plate systems provided are still the conventional "in stock" mini plates that can be individually designed by pre-bending according to the stereolithographic model of the patient. Custom made three-dimensional (3D) printed implants have earlier been demonstrated to be an ideal solution in deformity surgery and in reconstruction of complex posttraumatic cases. In this study, we report the novel use of patient-specific saw and drill guides combined with patient-specific 3D titanium alloy implants as a fixation system in maxillary movement after Le Fort I and bimaxillary osteotomies (n = 32). The implants were individually designed for each patient to follow anatomical structures and to provide exact positioning and stability of the repositioned maxilla.

Rehabilitation of the severely atrophied dentoalveolar ridge in the aesthetic region with corticocancellous grafts from the iliac crest and dental implants

BACKGROUND: the aim of this study was to assess changes in bone volume after block bone augmentation and placement of dental implants and further evaluate the aesthetic outcome of the treatment. MATERIAL AND METHODS: 9 patients with atrophied anterior maxilla were included in this study. They received total of 21 implants. Dimensions of the alveolar ridge were measured from cone-beam computed tomography x-rays. The bone level at the implant sites was analysed from intraoral x-rays and the aesthetic outcome was assessed from clinical photographs using a pink aesthetic score (pes) scaling. RESULTS: The mean gained horizontal bone width at the marginal crest and 5 mm apically was accordingly 2.7mm and 5.0 mm. The mean pes rating was 9.8/14. The survival rate of. CONCLUSIONS: Reconstruction of the atrophied anterior maxilla with bone blocks and dental implants is a safe procedure with high survival rate and acceptable aesthetic outcome

Rapid prototyping modelling in oral and maxillofacial surgery: A two year retrospective study.

BACKGROUND: The use of rapid prototyping (RP) models in medicine to construct bony models is increasing. MATERIAL AND METHODS: The aim of the study was to evaluate retrospectively the indication for the use of RP models in oral and maxillofacial surgery at Helsinki University Central Hospital during 2009-2010. Also, the used computed tomography (CT) examination - multislice CT (MSCT) or cone beam CT (CBCT) - method was evaluated. RESULTS: In total 114 RP models were fabricated for 102 patients. The mean age of the patients at the time of the production of the model was 50.4 years. The indications for the modelling included malignant lesions (29%), secondary reconstruction (25%), prosthodontic treatment (22%), orthognathic surgery or asymmetry (13%), benign lesions (8%), and TMJ disorders (4%). MSCT examination was used in 92 and CBCT examination in 22 cases. Most of the models (75%) were conventional hard tissue models. Models with colored tumour or other structure(s) of interest were ordered in 24%. Two out of the 114 models were soft tissue models. CONCLUSIONS: The main benefit of the models was in treatment planning and in connection with the production of pre-bent plates or custom made implants. The RP models both facilitate and improve treatment planning and intraoperative efficiency. KEY WORDS: Rapid prototyping, radiology, computed tomography, cone beam computed tomography.

Rapid prototyped patient specific implants for reconstruction of orbital wall defects.

Defects of orbital walls can be reconstructed using implants. The authors report a safe and accurate method to reconstruct bone defects in the orbital area using patient specific implants. A detailed process description of computer aided design (CAD) reconstructive surgery (CRS) is introduced in this prospective study. The 3D volumetric virtual implant was design using MSCT data and PTCProEngineer™ 3D software. The intact orbital cavity of twelve patients was mirrored to the injured side. Specific ledges steered the implant into correct place. Postoperatively the position was assessed using image fusion. One implant (8%) was rejected due to chemical impurities, two (16%) had a false shape due to incorrect CAD. Data of thin bone did not transfer correctly to CAD and resulted in error. One implant (8%) was placed incorrectly. Duration of the CRS was in average 1.17 h, correspondingly 1.57 h using intraoperative bending technique. The CRS process has several critical stages, which are related to converting data and to incompatibility between software. The CRS process has several steps that need further studies. The data of thin bone may be lost and disturb an otherwise very precise technique. The risk of incorporating impurities into the implant must be carefully controlled.

Increase in VEGF secretion from human fibroblast cells by bioactive glass S53P4 to stimulate angiogenesis in bone.

Bioactive glasses (BAGs) are being investigated for the repair and reconstruction of bone defects, as they exhibit osteoconductive and osteostimulatory potential. However, successful bone regeneration requires also the neovascularization of the construct which is, among other factors, guided by vascular endothelial growth factor (VEGF). In this study, BAG S53P4 (53% SiO2 , 23% Na2 O, 20% CaO, 4% P2 O5 ) is investigated in relation to VEGF-release and response of fibroblast cells. Human CD-18CO fibroblasts were cultivated in contact with different granules of different sizes (0.5-0.8 mm, 1.0-2.0 mm, and 2.0-3.15 mm) and at different concentrations (0-1 wt/vol % of BAG) for 72 h. The analysis of morphology revealed no toxic effect for all granule sizes and concentrations. Compared with the reference, lactate dehydrogenase-activity of CCD-18CO cells increased in contact with BAG samples. The VEGF release from CCD-18CO fibroblasts cultured on different granule sizes and at different concentrations after 72 h of incubation was quantified. It was found that particles of 0.5-0.8 mm and 1.0-2.0 mm in size enhanced VEGF release, whereas BAG particle sizes of 2.0-3.15 mm led to inhibition of VEGF release. The results are relevant to understand the influence of the particle size and concentration of BAG S53P4 on VEGF expression and neovascularization.