Long-Term Outcomes After External Maxillary Distraction Surgery in Patients With Down Syndrome.

BACKGROUND: Patients with Down syndrome have severe facial deformities that can precipitate functional consequences and social stigmatization. Craniofacial surgical intervention can play a role in improving these symptoms and patient quality of life. The objective of this study was to investigate the long-term outcomes of distraction osteogenesis and orthognathic surgical intervention in patients with Down syndrome. MATERIALS AND METHODS: Charts of 3 patients with Down syndrome who were treated with external maxillary distraction osteogenesis were retrospectively reviewed. The patients' caregivers were prospectively interviewed between 10 and 15 years after surgery to determine surgical stability, long-term function, and quality of life status. RESULTS: All patients and their caregivers reported excellent results with improvements in function and quality of life. Facial skeletal changes have been stable over time. The cephalometric analysis demonstrated significant maxillary advancement in all 3 patients and mandibular changes to correct mandibular prognathism and asymmetry in the patient who underwent finishing orthognathic surgery. CONCLUSIONS: External maxillary distraction osteogenesis and orthognathic surgery may be considered in select patients with Down syndrome as part of their multidisciplinary health care. These interventions can result in long-term improvements in patient function and quality of life.

Neural networks for classification of cervical vertebrae maturation: a systematic review.

OBJECTIVE: To assess the accuracy of identification and/or classification of the stage of cervical vertebrae maturity on lateral cephalograms by neural networks as compared with the ground truth determined by human observers. MATERIALS AND METHODS: Search results from four electronic databases (PubMed [MEDLINE], Embase, Scopus, and Web of Science) were screened by two independent reviewers, and potentially relevant articles were chosen for full-text evaluation. Articles that fulfilled the inclusion criteria were selected for data extraction and methodologic assessment by the QUADAS-2 tool. RESULTS: The search identified 425 articles across the databases, from which 8 were selected for inclusion. Most publications concerned the development of the models with different input features. Performance of the systems was evaluated against the classifications performed by human observers. The accuracy of the models on the test data ranged from 50% to more than 90%. There were concerns in all studies regarding the risk of bias in the index test and the reference standards. Studies that compared models with other algorithms in machine learning showed better results using neural networks. CONCLUSIONS: Neural networks can detect and classify cervical vertebrae maturation stages on lateral cephalograms. However, further studies need to develop robust models using appropriate reference standards that can be generalized to external data.

The usefulness of cone-beam computed tomography gray values for alveolar bone linear measurements.

OBJECTIVES: To test a proof-of-concept that the accuracy and reliability of alveolar bone height measurements from orthodontic grade (large field-of-view [FOV], large voxel-size) cone-beam computed tomography (CBCT) images may be improved by using pixel gray values. MATERIALS AND METHODS: Twenty fresh cadaver pig heads underwent CBCT scans (17 × 23 cm FOV, 0.4-mm voxel size). Buccal alveolar bone heights of maxillary first molars were measured using the conventional vision-based (VB) and the proposed gray value-assisted (GVA) methods. The GVA methods entailed localization of landmarks through observation of gray value pattern changes across tissue boundaries followed by mathematical calculation of distances between landmark pixels. Interrater reliability and accuracy of CBCT measurements made by all methods were statistically analyzed by comparing with physical measurements (gold standards). RESULTS: The interrater reliability of CBCT measurements made by GVA methods was comparable to physical measurements but higher than those made by the VB method. The GVA (bend-down pattern) method yielded average measurements similar to physical measurements, while those obtained by the VB and the GVA (straight pattern) methods were significantly larger (repeated measures analysis of variance, P < .001). The GVA (bend-down pattern) method also produced significantly more measurements within one voxel size of physical measurements than did the VB and GVA (straight pattern) methods (Chi-square tests, P < .017). CONCLUSIONS: These data confirm a concept that local gray value change patterns may be used to improve the accuracy and reliability of alveolar bone height measurement from large FOV and large voxel-size CBCT images.

Patients', parents', and orthodontists' perceptions of the need for and costs of additional procedures to reduce treatment time.

INTRODUCTION: The purpose of this study was to evaluate patients', parents', and orthodontists' perspectives on orthodontic treatment duration and techniques for accelerating the rate of tooth movement. METHODS: Adolescent patients (n = 200) and their parents (n = 200), and adult patients (n = 50) from a multidoctor practice were personally surveyed regarding treatment duration and acceptance of appliances and techniques to enhance the speed of orthodontic treatment, and how much increase in fees they were willing to pay for these. Members of the American Association of Orthodontists were surveyed electronically regarding their willingness to use these techniques and appliances and the costs they were willing to pay for them. RESULTS: A total of 683 orthodontists replied to the electronic survey (7.5%). Approximately 70% of the orthodontists who replied to the survey were interested in adopting additional clinical procedures to reduce treatment time. No significant association was found between practice characteristics and interest in adopting clinical procedures to reduce treatment time. The invasiveness of the procedure was inversely related to its acceptance in all groups surveyed. Most orthodontists are willing to pay only up to 20% of their treatment fee to companies for the use of technologies that reduce treatment time, and most patients and parents were willing to pay only up to a 20% increase in fees for these approaches. Orthodontists thought that increases in the rate of tooth movement could pose a problem for fee collection. CONCLUSIONS: Orthodontists and patients alike are interested in techniques that can accelerate tooth movement. Similarities between all groups were found regarding the acceptance of different approaches to accelerate tooth movement and the percentage of the orthodontic fee that would be paid for these techniques. Less-invasive techniques had greater acceptability in all groups.

Cone-beam computed tomography evaluation of alveolar ridge width and height changes after orthodontic space opening in patients with congenitally missing maxillary lateral incisors.

INTRODUCTION: The purpose of this study was to evaluate the alveolar bone dimensional changes with cone-beam computed tomography after space-opening procedures for an endosseous implant in patients with unilateral or bilateral maxillary lateral incisor agenesis. METHODS: A pilot retrospective cohort study was conducted of 11 patients (13 sites) in whom the canines had erupted less than 2 mm distally to the central incisors. Pretreatment and posttreatment scans obtained from 3 private practice offices were evaluated for changes in alveolar bone width, height, and labial concavity. A fiducial line representing the ideal location of the longitudinal axis of an endosseous dental implant was used as a reference for the spatial location of the alveolar bone at the lateral incisor site in reference to the adjacent tooth roots at posttreatment. The posttreatment width and height measurements scans were compared with normative data from the contralateral incisor in patients with unilateral agenesis (n = 6). RESULTS: Alveolar bone width was significantly decreased on average from 17% to 25% along the height of the ridge (2-10 mm) (P <0.05). The labial concavity was significantly increased compared with the initial dimensions (P <0.05). No significant changes were found in alveolar bone ridge height. CONCLUSIONS: Significant alveolar bone width decreases and increases in labial concavity were found after implant ridge development in patients with maxillary lateral incisor agenesis. The alveolar bone ridge was located more lingually than the adjacent teeth, suggesting a need for bone grafting to achieve proper fixture placement.

Alveolar ridge width and height changes after orthodontic space opening in patients congenitally missing maxillary lateral incisors.

The purpose of this study was to evaluate the dimensional changes of the alveolar ridge in patients with congenitally missing maxillary lateral incisors. The width and height of the alveolar ridge were compared before and after opening space for an endosseous dental implant between the central incisor and canine. Pre- and post-treatment dental stone models of 31 patients (8 males, 23 females; mean age 15.1 ± 7.9 years pre-treatment, 17.6 ± 8 years post-treatment) with unilaterally or bilaterally, congenitally missing maxillary lateral incisors were used in this study. Pre- and post-treatment measurements included: the space between the maxillary central incisor and canine, the depth of the labial concavity, and the width and height of the lateral incisor alveolar ridge. Two different techniques were used to measure the ridge width. Student's paired samples t-test was used to test for significance. The alveolar ridge underwent statistically significant width loss (Method 1: 4-8 per cent, Method 2: 13-15 per cent) during the course of orthodontic treatment. A 6-12 per cent loss in ridge height was also noted. The depth of the labial concavity between the maxillary central incisor and canine nearly doubled. There was a significant decrease in the width and height of the alveolar ridge in patients congenitally missing a maxillary lateral incisor who received orthodontic treatment to create space for an endosseous dental implant.

Comparative evaluation of condylar position in symptomatic (TMJ dysfunction) and asymptomatic individuals.

CONTEXT: The etiopathogenesis of temporomandibular joint (TMJ) disorders has been attributed to multiple factors and, while the importance of centric relation (CR) has been acknowledged in dental literature, the role of condylar position and CR-CO (CO-centric occlusion) discrepancy in TMJ dysfunction (TMD) has been a source of controversy. AIM: To establish the relationship between condyle position and TMD. SETTING AND DESIGN: This was a case-control study to evaluate condylar displacement and interarch CR-CO discrepancy in symptomatic subjects (with TMD) and compare them with asymptomatic subjects. MATERIALS AND METHODS: Forty subjects were screened for TMD based on Helkimo index and grouped into asymptomatic and symptomatic groups. CR was registered using the modified Roth power centric bite registration after neuromuscular deprogramming. Models thus mounted on an Advanced Dental Design (AD2) articulator were evaluated for interarch CR-CO discrepancy. The condylar position discrepancy was recorded on a device MCD (measured condylar deviation). STATISTICAL ANALYSIS: The Student's t test was used to test statistical significance. The paired t test and the unpaired t test were used for comparing results within and between the groups. Pearson correlation coefficient was used to find out the correlation between MCD measurements and dental three-dimensional (3D) model analysis measurements. The Chi-square test was used to evaluate the qualitative data. RESULTS: The average vertical and horizontal condylar displacements were significantly greater in the symptomatic group than in the asymptomatic group. There were significant deviations at the level of the occlusion in both groups. CONCLUSION: Condyle position may play a significant role in the etiopathogenesis of TMJ disorders.

Short-term zoledronic acid reduces trabecular bone remodeling in dogs.

The effects of zoledronic acid, a bisphosphonate, on the trabecular bone remodeling (TBR) of the mandibular condyle are unknown. The objectives of this study were to quantify and compare TBR in the mandibular condyle and vertebrae of 2- to 3-yr-old dogs and to evaluate the effects of short-term zoledronic acid on TBR. Bone samples from two, age-matched groups of dogs [seven dogs were given no treatment (NT group) and seven dogs were treated with four total infusions of zoledronic acid administered monthly (ZOL group)] were analyzed using histomorphometry. Trabecular bone remodeling and microarchitecture were quantified and analyzed statistically. Physiologic TBR, quantified in the NT group, was significantly higher (more than sixfold) in the vertebrae than in the mandibular condyle. Trabecular bone remodeling in the vertebrae of dogs of the ZOL group was 96% lower than in dogs of the NT group. By contrast, TBR in the mandibular condyle of dogs in the ZOL group was statistically equivalent to that of dogs in the NT group. Our results demonstrate that the physiological TBR in aged dogs is vastly different in the mandibular condyle compared to that in the vertebra. A higher level of physiologic TBR in the vertebra than in the mandibular condyle results in greater reduction of TBR in response to short-term treatment with zoledronic acid.