A review and evaluation of orthodontic brackets, molar bands and orthodontic auxiliaries during orthognathic surgery: A prospective cohort study.

OBJECTIVE: The primary aim of this study was to provide a review of the types and frequency of orthodontic brackets, molar bands and orthodontic auxiliaries used for patients undergoing orthognathic surgery. The secondary aim was to evaluate the risk of failure of these items during orthognathic surgery. METHODS: From three Dutch hospitals, 124 adult patients were included in this prospective cohort study. Five independent researchers collected the data during surgery using a specifically created data extraction form. The type of surgery, surgeon, orthodontist and type of orthodontic bracket, molar band or auxiliary were noted for each tooth. To evaluate their failure risk, the following variables were noted: failure and site; and type and cause of failure. RESULTS: Stainless-steel brackets were the most frequently (75.8%) used bracket type seen in patients undergoing orthognathic surgery. Ceramic brackets were seen in 24.2% of the cases and were only applied in the anterior region. Molar bands were present in 58.9% of the patients and mostly with bands on the first molars in combination with bonded tubes on the second molars. In 32.2% of all cases, one or more failures were noted. One-third of all failures were described as detachment of the molar tube on the most posterior molar. Kobayashi ligatures and powerpins showed the highest risk of failure (odds ratio [OR] 3.70, 95% confidence interval [CI] = 1.91-7.15). No significant difference in failure rate was found between stainless-steel brackets, molar bands (OR 0.34, 95% CI = 0.08-1.43) and ceramic brackets (OR 0.44, 95% CI = 0.14-1.45). CONCLUSION: Stainless-steel brackets, ceramic brackets, molar bands and surgical hooks are suitable for orthognathic cases. Kobayashi ligatures and powerpins had a significantly higher risk of failure so are not recommended for temporary intraoperative maxillomandibular fixation (TIO-MMF).

Facial deformation following treatment for pediatric head and neck rhabdomyosarcoma; the difference between treatment modalities. Results of a trans-Atlantic, multicenter cross-sectional cohort study.

BACKGROUND: The four different local therapy strategies used for head and neck rhabdomyosarcoma (HNRMS) include proton therapy (PT), photon therapy (RT), surgery with radiotherapy (Paris-method), and surgery with brachytherapy (AMORE). Local control and survival is comparable; however, the impact of these different treatments on facial deformation is still poorly understood. This study aims to quantify facial deformation and investigates the differences in facial deformation between treatment modalities. METHODS: Across four European and North American institutions, HNRMS survivors treated between 1990 and 2017, more than 2 years post treatment, had a 3D photograph taken. Using dense surface modeling, we computed facial signatures for each survivor to show facial deformation relative to 35 age-sex-ethnicity-matched controls. Additionally, we computed individual facial asymmetry. FINDINGS: A total of 173 HNRMS survivors were included, survivors showed significantly reduced facial growth (p < .001) compared to healthy controls. Partitioned by tumor site, there was reduced facial growth in survivors with nonparameningeal primaries (p = .002), and parameningeal primaries (p ≤.001), but not for orbital primaries (p = .080) All patients were significantly more asymmetric than healthy controls, independent of treatment modality (p ≤ .001). There was significantly more facial deformation in orbital patients when comparing RT to AMORE (p = .046). In survivors with a parameningeal tumor, there was significantly less facial deformation in PT when compared to RT (p = .009) and Paris-method (p = .007). INTERPRETATION: When selecting optimal treatment, musculoskeletal facial outcomes are an expected difference between treatment options. These anticipated differences are currently based on clinicians' bias, expertise, and experience. These data supplement clinician judgment with an objective analysis highlighting the impact of patient age and tumor site between existing treatment options.

Normal variation of mandibular asymmetry in children.

OBJECTIVE: To explore the normal variation of asymmetry in mandibles of children in the age group of 1 to 12 years. MATERIALS AND METHODS: The study group consisted of 92 cadaveric mandibles of children with a dental age of 1 to 12 years old in possession of ACTA (Academic Centre for Dentistry Amsterdam), Faculty of Dentistry, the Netherlands. 3D models of the mandibles were obtained from CT-scans and hemimandibular volumes of all mandibles were calculated. The condylar height, ramus height, mandibular body length and the gonial angle were bilaterally determined using a novel landmark-based method, and the degree of asymmetry was calculated. RESULTS: No relationship was found between dental age and asymmetry of the studied parameters (P < .05). The highest degree of asymmetry was found in the ramus height, whereas the gonial angle presented the lowest degree of asymmetry. A positive correlation was found between the asymmetry of the hemimandibular volume vs the height of the ramus (P < .05) and the length of the mandibular body (P < .05). An inverse correlation was found between the asymmetry of the ramus height vs the condylar height (P < .05), mandibular body length (P < .05) and gonial angle (P < .05). CONCLUSIONS: Mandibular asymmetries in children did occur (9.8% of the included mandibles presented with a relevant overall asymmetry of ≥3%) and were unrelated to age. The different segments of the mandible seem to compensate for each other, in order to maintain a functional equilibrium.

Interrater Reliability for Classifying Craniofacial Microsomia Severity: A Call for Objective Evaluation.

OBJECTIVE: The severity of craniofacial microsomia (CFM) is generally classified using the Orbit, Mandible, Ear, Soft tissue, Nerve (OMENS) classification score. The global assessment of the Phenotypic Assessment Tool for Craniofacial Microsomia (PAT-CFM), is a pictorial modification of the OMENS classification. The aim of this study was to assess the interrater reliability of the PAT-CFM global assessment score. DESIGN: In this prospective cohort study, three clinicians completed the global assessment form of the PAT-CFM. The mandible was classified based on orthopantomogram- and/or computed tomography images. PARTICIPANTS: Consecutive patients with CFM or microtia.Interrater agreement was calculated using the weighted Krippendorff alpha (α), with 95% confidence intervals (CI). RESULTS: In total, 53 patients were included (106 hemifaces). The reliabilities of the main classification components ranged from high for the mandible (α = 0.904 [95% CI 0.860-0.948]) and ear (α = 0.958 [95% CI 0.934-0.983]) subscales, to tentative for the orbital summary score (α = 0.682 [0.542-0.821]), and nerve summary score (α = 0.782 [0.666-0.900]) subscales. CONCLUSIONS: The reliability of the ear and radiographic mandible scales of the PAT-CFM global classification were high, while the orbit, facial nerve and soft tissue subscales may have limited reliability. Research focusing on radiographic severity scores for hypoplasia of the orbits and soft tissues, as well as objective measures for overall facial hypoplasia using non-ionizing forms of imaging for early classification, are warranted.

Quality of Life After Orthognathic Surgery in Patients with Cleft: An Overview of Available Patient-Reported Outcome Measures.

Measuring the impact of orthognathic surgery on quality of life is of significant importance in patients with cleft deformities. Standardized tools such as patient-reported outcome measures (PROMs) are needed to fully comprehend patients' needs and perceptions. Therefore, the availability of reliable, valid, and comprehensive questionnaires for patients is essential. The aim of this study is to identify PROMs measuring the impact of orthognathic surgery on quality of life in patients with cleft deformities and to evaluate the identified PROMs.A systematic search of the literature was performed according to the preferred reporting items for systematic reviews and meta-analysis guidelines. All validated PROMs, regarding the impact of orthognathic surgery on quality of life in patients with cleft deformities, were identified and assessed according to the quality criteria proposed for measurement properties of health status questionnaires.An electronic search yielded 577 articles. After a full-text review of 87 articles, 4 articles met the inclusion criteria, comprising 58 PROMs. Of these 58 PROMs, 1 PROM (the CLEFT-Q) has been validated to measure the impact of orthognathic surgery on patients with a facial cleft. Evaluation of methodological quality of the included articles and assessment of the measurement properties of the CLEFT-Q show that the CLEFT-Q scores relatively good for all available measurement properties, making it suitable for immediate use.The CLEFT-Q was found to be the only valid instrument so far to measure the impact of orthognathic surgery on the quality of life in patients with cleft deformities.

Evaluating International Diagnostic, Screening, and Monitoring Practices for Craniofacial Microsomia and Microtia: A Survey Study.

To (1) appraise current international classification and clinical management strategies for craniofacial microsomia (CFM) and microtia, and (2) to assess agreement with the European Reference Network "European Guideline Craniofacial Microsomia" recommendations on screening and monitoring.This was a cross-sectional online survey study. The survey consisted of 44 questions on demographics, diagnostics and classification, obstructive sleep apnea, feeding difficulties, speech and language development, hearing, ocular abnormalities, visual development, orthodontic screening, genetic counselling, psychological wellbeing, and extracraniofacial anomalies.Respondents were participants of 3 international cleft and craniofacial conferences, members of the American Cleft Palate and Craniofacial Association and members of the International Society for Auricular Reconstruction. Respondents were requested to complete 1 questionnaire per multidisciplinary team.Fifty-seven responses were received from 30 countries (response rate ∼3%).The International Consortium for Health Outcomes Measurement diagnostic criteria were used by 86% of respondents, though 65% considered isolated microtia a mild form of CFM. The Orbit, Mandible, Ear, Facial Nerve and Soft Tissue classification system was used by 74% of respondents. Agreement with standardized screening and monitoring recommendations was between 61% and 97%. A majority of respondents agreed with screening for extracraniofacial anomalies (63%-68%) and with genetic counselling (81%).This survey did not reveal consistent agreement on the diagnostic criteria for CFM. Respondents mostly supported management recommendations, but frequently disagreed with the standardization of care. Future studies could focus on working towards international consensus on diagnostic criteria, and exploring internationally feasible management strategies.

The Dutch Version of the Orthognathic Quality of Life Questionnaire (OQLQ-NL): Validation for Cleft Patients.

OBJECTIVE: The aim of this study is to validate the Dutch version of the Orthognathic Quality of Life Questionnaire (OQLQ-NL) for cleft patients who received orthognathic surgery. METHODS: To compare the OQLQ-NL with the CLEFT-Q, we used a convenience sample of thirty-two cleft patients. Using the Cronbach's alpha coefficient for multiple item scales, internal reliabilities of the OQLQ-NL were evaluated. The OQLQ-NL was repeated at a two-week interval and the intraclass correlation coefficient was calculated, to establish of the test-retest reliability. The construct validity of the OQLQ-NL was evaluated by using Spearman's correlation to test its correlation with the CLEFT-Q. RESULTS: Thirty-two patients filled in the OQLQ-NL and CLEFT-Q. The OQLQ-NL had excellent results in internal reliability and test-retest reliability. The vast majority of the correlations between the domains and scales of the questionnaires were as expected. Data from this study and previous studies confirm the construct validity of the OQLQ-NL. CONCLUSION: Our results suggest the OQLQ-NL is a valid and reliable instrument for measuring quality of life in cleft patients who have received orthognathic surgery in the Netherlands.

Technical Note on Three- and Four-Wall Orbital Reconstructions With Patient-Specific Implants.

ABSTRACT: Orbital reconstruction is one of the most complex procedures in maxillofacial surgery. It becomes even more complex when all references to the original anatomy are lost. The purpose of this article is to provide an overview of techniques for complex three- and four-wall orbital reconstructions. Preoperative virtual surgical planning is essential when considering different reconstruction possibilities. The considerations that may lead to different approaches are described, and the advantages and drawbacks of each technique are evaluated. It is recommended to reconstruct solitary three-wall or four-wall orbital defects with multiple patientspecific implants. Optimizations of this treatment protocol are suggested, and their effects on predictability are demonstrated in a case presentation of a four-wall defect reconstruction with multiple patient-specific implants.

The Orthognathic Quality of Life Questionnaire: Translation and Validation into Dutch.

OBJECTIVE: The aim of this study is to translate and validate the Orthognathic Quality of Life Questionnaire (OQLQ) in the Dutch language (OQLQ-NL). METHODS: The translation of the OQLQ into the Dutch language was performed following the guidelines for the Process of Cross-Cultural Adaption of Self-Report Measures. Sixty-two patients who received orthognathic surgery in the past 10 years were included for participation. Internal reliabilities of the OQLQ-NL were evaluated for multiple item scales with the use of the Cronbach alpha coefficient. For the establishment of the test-retest reliability, the OQLQ-NL was repeated with a 2-week interval and the intraclass correlation coefficient was calculated. Spearman correlation was used to test the correlation with the OHIP-49NL and the FACE-Q, to be able to evaluate the construct validity of the OQLQ-NL. RESULTS: Thirty-five patients filled in the OQLQ-NL, OHIP49NL, and FACE-Q upon arrival and 22 patients returned the OQLQ-NL after 2 weeks (response rate of 56.6% and 62.9%, respectively). The OQLQ-NL showed excellent results in internal reliability and test-retest reliability. The vast majority of the correlations between the domains of the questionnaires were as expected. Data from this study and previous studies confirm the construct validity of the OQLQ-NL. CONCLUSION: The OQLQ-NL appears to be a valid and reliable instrument to measure quality of life for patients receiving orthognathic surgery in the Netherlands.

Is Three-Dimensional Virtual Planning in Cranial Reconstruction for Advanced Cutaneous Squamous Cell Carcinoma of the Skull a Feasible Option?

BACKGROUND: Cutaneous squamous cell carcinoma (cSCC) is a common type of malignant skin disorder. An uncommon feature is local bony invasion, as can rarely be seen in lesions on the scalp. The optimal treatment strategy in these rare cases is still under debate. OBJECTIVE: The aim of this case report is to present a 1-stage three-dimensional planned surgical resection and reconstruction of a cSCC with bony invasion into the scalp and to discuss the alternative options and potential pitfalls. MATERIALS AND METHODS: A patient diagnosed with rT4N0M0 cSCC of the scalp underwent a cranial resection and reconstruction in 1 stage. With the use of computer-assisted design and computer-assisted manufacturing a patient-specific implant (PSI) of poly (ether ether ketone) was manufactured. After the PSI was inserted, it was covered with a latissimus dorsi muscle and a split-thickness skin graft. RESULTS: Intraoperatively the resection template generated an accurate resection and accurate and fast placement of the PSI. The reconstruction had a clinical satisfactory esthetic result, but was hampered by the development of a small wound dehiscence was observed over the postoperative course. CONCLUSION: Three-dimensional planned resection and reconstruction for composite defects of the skull after resection of a cSCC of the scalp with bony invasion may lead to an accurate and predictable resection and accurate and fast placement of the PSI. However, patient specific characteristics should be considered to assess potential risks and benefits before opting for this one-stage treatment strategy.

Should Virtual Mirroring Be Used in the Preoperative Planning of an Orbital Reconstruction?

PURPOSE: Mirroring has been used as a diagnostic tool in orbital wall fractures for many years, but limited research is available proving the assumed symmetry of orbits. The purpose of this study was to evaluate volume and contour differences between orbital cavities in healthy humans. MATERIALS AND METHODS: In this cross-sectional study, the left and right orbital cavities of a consecutive sample of patients' computed tomograms were measured. Inclusion criteria were patients with no sign of orbital or sinus pathology or fracture. Outcome variables were differences in volume and contour. Descriptive statistics and Student paired t test were used for data analysis of orbital volume and distance maps were used for analysis of orbital contour. RESULTS: The sample was composed of 100 patients with a mean age of 57; 50% were men. The total mean orbital volume was 27.53 ± 3.11 mL. Mean difference between cavities was 0.44 ± 0.31 mL or 1.59% (standard deviation [SD], 1.10%). The orbital contour showed high similarity, with an absolute mean left-versus-right difference of 0.82 mm (SD, 0.23 mm). CONCLUSION: The authors hypothesize that the measured differences between right and left orbital volumes and contours are clinically minor. In consequence, the use of mirroring tools as part of preoperative planning in orbital reconstruction is legitimate with the aim of simulating the pre-traumatized anatomy.

Impact of Bone Volume Upon Condylar Activity in Patients With Unilateral Condylar Hyperplasia.

PURPOSE: Unilateral condylar hyperplasia or hyperactivity (UCH) is a bone overgrowth disorder affecting the mandible. The purpose of this study was to determine the relations among age, condylar bone structure, condylar bone volume, and condylar bone activity on single-photon emission computed tomographic (SPECT) scans in patients with UCH. MATERIALS AND METHODS: This study included 20 patients with a clinical presentation of progressive mandibular asymmetry and a positive bone SPECT scan. A bone SPECT-derived standardized uptake value (bSUV) for the condylar region was determined. All patients underwent condylectomy to arrest further progression of the disease. The resected condyles were scanned with a micro-computed tomographic scanner (18-µm resolution). Bone architectural parameters were calculated with routine morphometric software. RESULTS: The mean bSUV of the condyle on the affected side was 15.32 (standard deviation [SD], 8.98) compared with 9.85 (SD, 4.40) on the nonaffected side (P = .0007). For trabecular bone structure, there was a nonsignificant correlation between the SUV of the affected condyle and the measured bone volume fraction (r = 0.13; P = .58) and trabecular thickness (r = 0.03; P = .90). CONCLUSION: No meaningful relation was found between condylar bone volume fraction and condylar activity on bone scan; therefore, the impact of bone volume fraction on the results of bone scans is limited. The measured condylar activity on SPECT scan seems to be primarily a reflection of the remodeling rate of bone.

Finding the Ledge: Sagittal Analysis of Bony Landmarks of the Orbit.

PURPOSE: This study determined the average distances and angles between anatomic landmarks within the orbit, with an emphasis on localization of the orbital process of the palatine bone. This information will help the surgeon with treatment planning and surgical procedures. PATIENTS AND METHODS: Four anatomic landmarks were identified retrospectively on computed tomograms of 100 adult Caucasian patients (50 men and 50 women): the top of the infraorbital margin superior to the infraorbital foramen (point A), the top of the orbital process of the palatine bone (point B), the anteriormost bony portion of the superior orbital fissure (point C), and the ventrolateral aspect of the bony entrance of the optic canal (point D). The distances between these points were measured, as were the angle between the medial wall of the orbit and a line connecting points A to D at the level of the optic nerve. RESULTS: The mean distances between the orbital rim (point A) and the orbital process of the palatine bone (point B) were 33.8 mm in men and 32.7 mm in women. Men had markedly larger bony orbits than women; however, women had a larger angle than men for the 2 orbits. CONCLUSION: Obtaining these measurements preoperatively can enable a safer and more predictable surgical approach to the orbit, which can help lower the risk of damaging important neighboring structures. A preformed reconstruction plate can be manufactured or a standard reconstruction plate can be customized according to these measurements; during reconstruction, they also can help adequately localize the posterior ledge, specifically the orbital process of the palatine bone. These 2 aspects could ensure a more precise reconstruction of the orbital floor.

An open-source, three-dimensional growth model of the mandible.

The available reference data for the mandible and mandibular growth consists primarily of two-dimensional linear or angular measurements. The aim of this study was to create the first open-source, three-dimensional statistical shape model of the mandible that spans the complete growth period. Computed tomography scans of 678 mandibles from children and young adults between 0 and 22 years old were included in the model. The mandibles were segmented using a semi-automatic or automatic (artificial intelligence-based) segmentation method. Point correspondence among the samples was achieved by rigid registration, followed by non-rigid registration of a symmetrical template onto each sample. The registration process was validated with adequate results. Principal component analysis was used to gain insight in the variation within the dataset and to investigate age-related changes and sexual dimorphism. The presented growth model is accessible globally and free-of-charge for scientists, physicians and forensic investigators for any kind of purpose deemed suitable. The versatility of the model opens up new possibilities in the fields of oral and maxillofacial surgery, forensic sciences or biological anthropology. In clinical settings, the model may aid diagnostic decision-making, treatment planning and treatment evaluation.

Management of Asymmetry.

Orthognathic surgery in asymmetric cases is challenging because of diversity and individuality. Clinical observations are of paramount importance and need to be systemically thorough. Three-dimensional diagnosis and virtual planning have been proven extremely helpful in facilitating treatment toward symmetry in difficult cases with increasing precision. Compared with orthognathic surgery in symmetric situations, asymmetries produce numerous pitfalls and provide opportunities for out-of-the-box procedures.

Influence of Surgeon Experience on Surgical Outcome of Maxillomandibular Advancement for Obstructive Sleep Apnea.

The primary aim of this study was to assess the association between clinical efficacy outcomes (i.e., polysomnography (PSG) results) of maxillomandibular advancement (MMA) and surgeons' experience. The second aim was to assess the association between the occurrence of postoperative complications of MMA and surgeons' experiences. Patients treated with MMA for moderate to severe obstructive sleep apnea (OSA) were enrolled in this retrospective study. The patient population was divided into two groups based on two different surgeons performing MMA. The associations between surgeons' experience on the one hand and PSG results and postoperative complications on the other hand were investigated. A total of 75 patients were included. There was no significant difference in baseline characteristics between the two groups. The reductions in apnea-hypopnea index and oxygen desaturation index were both significantly greater in group-B than group-A (p = 0.015 and 0.002, respectively). The overall success rate after MMA was 64.0%. There was a negative correlation between surgeon experience and surgical success (odds ratio: 0.963 [0.93, 1.00], p = 0.031). No significant association was found between surgeon experience and surgical cure. Additionally, there was no significant association between surgeon experience and the occurrence of postoperative complications. Within the limitations of this study, it is concluded that surgeon experience may have little to no influence on the clinical efficacy and safety of MMA surgery in OSA patients.

Assessment of Surgical Accuracy in Maxillomandibular Advancement Surgery for Obstructive Sleep Apnea: A Preliminary Analysis.

This retrospective study aimed to: (1) investigate the surgical accuracy of maxillomandibular advancement (MMA) in obstructive sleep apnea (OSA) patients, with a specific focus on maxillary and mandibular advancement and counter-clockwise rotation and (2) investigate the correlation between the amount of achieved advancement and the reduction in the relative apnea hypopnea index (AHI). Sixteen patients, for whom a three-dimensional virtual surgical plan was generated preoperatively and a computed tomography scan (CT) or cone-beam computer tomography (CBCT) was acquired postoperatively, were included. The postoperative CT or CBCT was compared to the virtual surgical plan, and differences in the mandibular and maxillary advancement and counter-clockwise rotation were assessed. Maxillary and mandibular advancement (median 3.1 mm, p = 0.002 and 2.3 mm, p = 0.03, respectively) and counter-clockwise rotation (median 3.7°, p = 0.006 and 4.7°, p = 0.001, respectively) were notably less than intended. A significant correlation was found between the planned maxillary advancement and the difference between the planned and actual maxillary advancement (p = 0.048; adjusted R2 = 0.1979) and also between the planned counter-clockwise rotation and the difference between the planned and actual counter-clockwise rotation for the mandible (p = 0.012; adjusted R2 = 0.3261). Neither the maxilla-first nor the mandible-first surgical sequence proved to be superior in terms of the ability to achieve the intended movements (p > 0.45). Despite a significant reduction (p = 0.001) in the apnea hypopnea index (AHI) from a median of 62.6 events/h to 19.4 events/h following MMA, no relationship was found between the extent of maxillary or mandibular advancement and AHI improvement in this small cohort (p = 0.389 and p = 0.387, respectively). This study underlines the necessity for surgeons and future research projects to be aware of surgical inaccuracies in MMA procedures for OSA patients. Additionally, further research is required to investigate if sufficient advancement is an important factor associated with MMA treatment outcome.

Personalized Medicine Workflow in Post-Traumatic Orbital Reconstruction.

Restoration of the orbit is the first and most predictable step in the surgical treatment of orbital fractures. Orbital reconstruction is keyhole surgery performed in a confined space. A technology-supported workflow called computer-assisted surgery (CAS) has become the standard for complex orbital traumatology in many hospitals. CAS technology has catalyzed the incorporation of personalized medicine in orbital reconstruction. The complete workflow consists of diagnostics, planning, surgery and evaluation. Advanced diagnostics and virtual surgical planning are techniques utilized in the preoperative phase to optimally prepare for surgery and adapt the treatment to the patient. Further personalization of the treatment is possible if reconstruction is performed with a patient-specific implant and several design options are available to tailor the implant to individual needs. Intraoperatively, visual appraisal is used to assess the obtained implant position. Surgical navigation, intraoperative imaging, and specific PSI design options are able to enhance feedback in the CAS workflow. Evaluation of the surgical result can be performed both qualitatively and quantitatively. Throughout the entire workflow, the concepts of CAS and personalized medicine are intertwined. A combination of the techniques may be applied in order to achieve the most optimal clinical outcome. The goal of this article is to provide a complete overview of the workflow for post-traumatic orbital reconstruction, with an in-depth description of the available personalization and CAS options.

Complications in transpalatal distraction osteogenesis: a retrospective clinical study.

PURPOSE: Transpalatal distraction osteogenesis is a bone-borne technique to expand the maxilla and has become a routine method in treating patients with transverse maxillary hypoplasia. Limited reports concerning treatment difficulties have been published. The purpose of this study was to investigate and categorize the short- and middle-term incidence of peri- and postoperative difficulties (categorized by the classification of Paley in problems, obstacles, and complications). The signs of adverse dental and periodontal effects were established at least 1 year after removal of the distractor. PATIENTS AND METHODS: A total of 73 patients (27 male, 46 female; mean age: 28 years; range: 9-59) that underwent bone-borne SARPE in 3 centers were retrospectively investigated. Clinical follow-up was performed in 63 patients after an average period of 23.9 months (range: 6-63 months). RESULTS: Twenty-seven problems (mainly appliance related), 10 obstacles (appliance-related and asymmetric maxillary expansion), and 1 complication (premature loss of the TPD-module, due to lack of space, in a cleft patient) occurred. Clinical examination showed minimal periodontal damage (gingival recession on 15 sites and pocket depths 4-5 mm in 11 sites). In 28.6% of the incisors radiographic signs of external apical root resorption were seen. CONCLUSION: Bone-borne SARPE is a reliable technique with predictable outcomes. These results suggest that bone-borne SARPE is associated with a low incidence of dental and periodontal damage. Nevertheless, further research, preferably in randomized controlled design, is needed to evaluate the long-term effects and stability.

Measurements on 3D models of human skulls derived from two different cone beam CT scanners.

The aims of this study were to compare measurements on three-dimensional (3D) models of human skulls derived from two different cone beam CT scanners (CBCT) and to evaluate if the used hardware can influence the performed measurements. CBCT scans of 40 dry human skulls with both the i-CAT and the Iluma cone beam CT scanners were made. From the CBCT scans, 3D models were constructed. One operator identified 19 landmarks five times on both types of 3D models with a time interval of 1 week. Intra-observer reliability was high for most measurements. There was a statistically significant and clinically relevant difference for some measurements between constructed 3D models of the same skull from the two different CBCT devices. Used hardware for scanning might influence the measurements performed. This means that care should be taken when interpreting measurements made on CBCT 3D models derived from different CBCT devices.