Effect of Material and Pad Abrasion on Shear Bond Strength of 3D-Printed Orthodontic Brackets.

OBJECTIVE: To investigate the effect of printing material and air abrasion of bracket pads on the shear bond strength of 3D-printed plastic orthodontic brackets when bonded to the enamel of extracted human teeth. MATERIALS AND METHODS: Premolar brackets were 3D-printed using the design of a commercially available plastic bracket in two biocompatible resins: Dental LT Resin and Dental SG Resin (n = 40/material). 3D-printed brackets and commercially manufactured plastic brackets were divided into two groups (n = 20/group), one of which was air abraded. All brackets were bonded to extracted human premolars, and shear bond strength tests were performed. The failure types of each sample were classified using a 5-category modified adhesive remnant index (ARI) scoring system. RESULTS: Bracket material and bracket pad surface treatment presented statistically significant effects for shear bond strengths, and a significant interaction effect between bracket material and bracket pad surface treatment was observed. The non-air abraded (NAA) SG group (8.87 ± 0.64 MPa) had a statistically significantly lower shear bond strength than the air abraded (AA) SG group (12.09 ± 1.23 MPa). In the manufactured brackets and LT Resin groups, the NAA and AA groups were not statistically significantly different within each resin. A significant effect of bracket material and bracket pad surface treatment on ARI score was observed, but no significant interaction effect between bracket material and pad treatment was found. CONCLUSION: 3D-printed orthodontic brackets presented clinically sufficient shear bond strengths both with and without AA prior to bonding. The effect of bracket pad AA on shear bond strength depends on the bracket material.

Quantifying Free Fibula Flap Growth After Pediatric Mandibular Reconstruction.

INTRODUCTION: The free fibula flap (FFF) is a preferred option for adult mandibular reconstruction. Due to skeletal immaturity, its routine use in pediatric patients remains in question. Inconsistencies regarding the ability of the FFF to grow in concordance with the patients' natural growth currently exist in the literature. The purpose of this report is to quantify mandibular growth in a young patient undergoing partial hemi-mandibular reconstruction with a FFF utilizing advanced three-dimensional software. METHODS: A 2-year old underwent left hemi-mandibular reconstruction with a FFF following resection of a desmoid tumor. The condyle was preserved. Using 3D software, changes in mandibular growth and morphology were evaluated based on preoperative (2.1 years old) and postoperative (2.5 years and 5.2 years old) computed tomography imaging. RESULTS: Mandibular growth occurred throughout the mandible in both postoperative evaluations. Greatest growth was seen in the ramus height. Fibula growth was also seen when comparing measurements to the virtual surgical planning guide. A novel parts comparison analysis revealed the greatest growth potential occurred at the condyle. CONCLUSION: Providing an objective evaluation using 3D software, we have demonstrated growth throughout the reconstructed mandible, with greatest growth occurring at the preserved condyle. Despite scientific limitations of our study, the potential for mandibular growth appears to remain after FFF reconstruction, offering successful functional and cosmetic outcomes.

Quantification of Mandibular Morphology in Pierre Robin Sequence to Optimize Mandibular Distraction Osteogenesis.

BACKGROUND: Mandibular distraction osteogenesis (MDO) is the primary surgical intervention to treat airway obstruction in Pierre Robin sequence (PRS). Current morphologic studies of PRS mandibles do not translate into providing airway management decisions. We compare mandibles of infants with nonsyndromic PRS to controls characterizing morphological variances relevant to distraction. We also examine how morphologic measurements and airway grades correlate with airway management. METHODS: Patients with PRS under 2 months old were age and sex matched to controls. Demographic and perioperative data, and Cormack-Lehane airway grades were recorded. Computed tomography scans were used to generate mandibular models. Bilateral condylions, gonions, and the menton were identified. Linear and angular measurements were made. Wilcoxon rank sum and 2-sample t tests were performed. RESULTS: Twenty-four patients with PRS and 24 controls were included. Seventeen patients with PRS required MDO. PRS patients had shorter ramus heights (16.7 vs 17.3 mm; P = .346) and mandibular body lengths (35.3 vs 39.3 mm; P < .001), more acute gonial angles (125.3° vs 131.3°; P < .001), and more obtuse intergonial angles (94.2° vs 80.4°; P < .001) compared to controls. No significant differences were found among patients requiring MDO versus conservative management nor among distracted patients with high versus low airway grades. CONCLUSION: Our study examines the largest and youngest PRS population to date regarding management of early airway obstruction with MDO. Our findings indicate that univector mandibular body distraction allows for normalization in nonsyndromic patients with PRS, and airway obstruction management decisions should remain clinical.

Speech Outcomes After LeFort I Advancement Among Cleft Lip and Palate Patients.

BACKGROUND: Velopharyngeal insufficiency (VPI) results from incomplete closure of the velopharyngeal (VP) sphincter with oral pressure consonants during speech. Maxillary hypoplasia is common among cleft children and often requires LeFort I advancement. This results in anterior movement of the soft palate with the bony maxillary segment. Consequently, the size of the VP sphincter is increased and may result postoperative VPI or worsening of prior VPI. To better counsel our patients and their families of the risk of VPI after LeFort I advancement, we chose to evaluate our own cohort. METHODS: We conducted an institutional review board-approved prospective review of all cleft children presenting to Texas Children's Hospital who underwent LeFort I advancement after previous palatoplasty between 2013 and 2016 in a three-surgeon, consecutive patient series. Data collected included age, sex, ethnicity, cleft type, prior secondary speech surgery, presence of preoperative fistula, planned distance of advancement, orthognathic surgery performed, and any concurrent procedures performed. Primary outcomes measured included preoperative and postoperative VP function and hypernasality as measured by a certified speech pathologist. RESULTS: Velopharyngeal function was unchanged in 67% of our cohort after LeFort I advancement. Of those patients, 83% had evidence of VPI preoperatively, and 17% had normal speech preoperatively. Twenty-two percent of the patients displayed worsening VP function after surgery, and 6% displayed evidence of improvement. Velopharyngeal function was unable to be assessed in 6% of patients. Nasality ratings worsened in 39% of patients, were unchanged in 39%, and improved in 22%. Of the patients with incompetent VP function after surgery, 50% already received or are currently scheduled for secondary speech surgery, 25% declined secondary surgery, and 25% are pending scheduling. CONCLUSIONS: Although VP function remains unchanged in a majority of patients after LeFort I advancement, VPI should be carefully screened for after surgery. If detected, secondary operations to correct speech should be strongly considered.

Cranial Anchored Mandible Distraction Osteogenesis.

Multiple or large distance mandibular distraction osteogenesis (MDO) in the older child is often complicated by iatrogenic temporomandibular joint (TMJ) pathology. The transmission of significant force to the TMJ in these particular patients is due to the greater distance of distraction required and the relative inelasticity of the soft tissue envelope. The authors present a clinical report of a successful asymmetrically vectored large distance MDO in a 13-year-old female with bilateral craniofacial microsomia with Goldenhar syndrome. During distraction, the TMJ joints were effectively unloaded from the forces of distraction using external bilateral cranial anchored devices (Cranio-Mandibular Fixator; KLS Martin, Jacksonville, FL). Angle's occlusion, facial angle, and evidence of TMJ pathology were assessed.

Craniofacial Manifestations in Severe Nemaline Myopathy.

Nemaline myopathy (NM) is a rare congenital muscular disease characterized by the presence of rod (nemaline) bodies visualized on muscle biopsy. The disease is genetically and clinically heterogeneous, and the age of onset can vary from neonate to adult. Patients typically present initially with diffuse muscle weakness and hypotonia. The disease also afflicts facial musculature and can cause anomalous facial growth and development. The authors report a patient of early onset NM with significant craniofacial abnormalities. The untreated facial growth is discussed and illustrated in this article. The authors reviewed the current knowledge in the literature regarding the molecular and genetic pathogenesis of NM. The roles of both surgical and supportive management are discussed in this particular patient.

A Standard Set of Outcome Measures for the Comprehensive Appraisal of Cleft Care.

Care of the patient with cleft lip and/or palate remains complex. Prior attempts at aggregating data to study the effectiveness of specific interventions or overall treatment protocols have been hindered by a lack of data standards. There exists a critical need to better define the outcomes-particularly those that matter most to patients and their families-and to standardize the methods by which these outcomes will be measured. This report summarizes the recommendations of an international, multidisciplinary working group with regard to which outcomes a typical cleft team could track, how those outcomes could be measured and recorded, and what strategies may be employed to sustainably implement a system for prospective data collection. It is only by agreeing on a common, standard set of outcome measures for the comprehensive appraisal of cleft care that intercenter comparisons can become possible. This is important for quality-improvement endeavors, comparative effectiveness research, and value-based health-care reform.

Effect of print layer height and printer type on the accuracy of 3-dimensional printed orthodontic models.

INTRODUCTION: Three-dimensional (3D) printing technologies enable production of orthodontic models from digital files; yet a range of variables associated with the process could impact the accuracy and clinical utility of the models. The objective of this study was to investigate the effect of print layer height on the accuracy of orthodontic models printed 3 dimensionally using a stereolithography format printer and to compare the accuracy of orthodontic models fabricated with several commercially available 3D printers. METHODS: Thirty-six identical models were produced with a stereolithography-based 3D printer using 3 layer heights (n = 12 per group): 25, 50, and 100 µm. Forty-eight additional models were printed using 4 commercially available 3D printers (n = 12 per group). Each printed model was digitally scanned and compared with the input file via superimposition analysis using a best-fit algorithm to assess accuracy. RESULTS: Statistically significant differences were found in the average overall deviations of models printed at each layer height, with the 25-µm and 100-µm layer height groups having the greatest and least deviations, respectively. Statistically significant differences were also found in the average overall deviations of models produced using the various 3D printer models, but all values fell within clinically acceptable limits. CONCLUSIONS: The print layer height and printer model can affect the accuracy of a 3D printed orthodontic model, but the impact should be considered with respect to the clinical tolerances associated with the envisioned application.

Orthodontist's Role in Orthognathic Surgery.

Orthognathic surgery can eliminate severe esthetic and functional deformities and be a life-changing event for a patient. An orthodontist's role in orthognathic surgery can be divided into several phases: the initial evaluation, presurgical orthodontics, surgical planning, and postsurgical orthodontics. At each of these phases, collaboration between the orthodontist and the surgeon is critical. The ability of an orthodontist and a surgeon to coordinate their efforts during this time is what will lead to a successful outcome.

Management of pediatric mandible fractures.

When determining the optimal treatment strategy for a pediatric mandible fracture, planning must factor in the patient's age, anatomy, stage of dental development, fracture site, and ability to cooperate with the proposed treatment plan. Careful consideration must be given to the possibility of long-term growth disturbance with various fracture locations and types of treatment. This article reviews the current principles of the management of pediatric mandibular fractures.