External Cervical Resorption: A Volumetric Analysis on Evolution of Defects over Time.

INTRODUCTION: The aim of this study was to assess the temporal evolution of external cervical resorption (ECR) defects using a volumetric quantification method. METHODS: Cone-beam computed tomographic (CBCT) images of patients diagnosed with ECR who chose not to receive treatment and attended recalls were collected. ECR defects were segmented in CBCT images at baseline and recall, and their volumes were quantified. The volumetric ratio of resorption defects/teeth was calculated. Three-dimensional classification of defects at baseline and recall and the prevalence of root surface perforations ≥1 mm were determined. The Wilcoxon matched pairs signed rank test, chi-square test, and linear regression models were used to analyze the data. RESULTS: Fifteen patients with 20 teeth diagnosed with ECR and an average recall time of 21 months were included. Nine (45%) teeth showed a change in 3-dimensional classification at recall. The volume of resorption defects (P = .0001) and the volumetric ratio of resorption defects/teeth (P = .0001) increased over time. The prevalence of root surface perforations ≥1 mm was higher at recall (n = 17, 85%) compared with baseline (n = 9, 45%) (P = .008). Linear regression models showed significant associations between the resorption defect volume at recall compared with baseline (P < .0001; 95% confidence interval, 0.053-0.081) and the volumetric ratio of resorption defects/teeth at recall compared with baseline (P < .0001; 95% confidence interval, 0.205-0.356). There was no association between the volume of resorption defects at recall with the length of the recall period, sex, or age (P > .05). CONCLUSIONS: When left untreated, ECR defects can increase in size and develop more root surface perforations. ECR has a dynamic nature, and its volumetric increase over time does not result from uniform/linear expansion of the defects.

A Volumetric Assessment of External Cervical Resorption Cases and Its Correlation to Classification, Treatment Planning, and Expected Prognosis.

INTRODUCTION: External cervical resorption (ECR) is a relatively uncommon type of external resorption; its treatment planning and prognosis are largely dependent on the clinician's subjective assessment. This study aimed to provide a volumetric assessment of ECR cases while correlating them to the Heithersay classification, treatment decision, and prognosis determined by 3 calibrated, independent evaluators. METHODS: A total of 168 ECR cases with corresponding periapical radiographs and cone-beam computed tomographic (CBCT) imaging were included in this study. An oral and maxillofacial radiologist calculated the volume occupied by the resorptive defects in root structures on CBCT imaging using Amira software (Thermo Scientific, Waltham, MA). Also, 3 board-certified endodontists evaluated anonymized and randomized periapical radiographs and corresponding CBCT images in separate sessions. Examiners were asked to provide a Heithersay classification, whether they would surgically repair the ECR lesion, and the expected prognosis of each case. RESULTS: The percentage of radicular volume affected by ECR ranged from 0.5%-58% with a median of 12%. The volumetric quantification of ECR best correlated with classification and prognosis assigned by the independent examiners using CBCT evaluation. The greatest variation in agreement was observed on whether to surgically repair the ECR. However, examiners agreed more uniformly on not to treat when the resorptive port of entry was found on either the lingual or proximal surfaces of the tooth. CONCLUSIONS: For the first time, the volumetric quantification of resorptive defects was calculated in vivo and correlated to the Heithersay classification and prognosis. Because the longevity of teeth affected with ECR depends on the integrity of the remaining root, the findings of this study provide important information to help clinicians decide on treatment planning and inform their patients of the expected prognosis. Future studies should focus on automating volumetric assessments of ECR to aid in unbiased chairside treatment planning decisions.

Multidetector CT of Mandibular Fractures, Reductions, and Complications: A Clinically Relevant Primer for the Radiologist.

After the nasal bones, the mandible is the second most common site of facial fractures, and mandibular fractures frequently require open reduction. In the trauma injury setting, multidetector computed tomography (CT) has become the cornerstone imaging modality for determining the most appropriate treatment management, fixation method, and surgical approach. Multidetector CT is also used to assess the adequacy of the reduction and evaluate potential complications in the postoperative period. For successful restoration of the mandible's form and function, as well as management of posttraumatic and postoperative complications, reconstructive surgeons are required to have a detailed understanding of mandibular biomechanics, occlusion, and anatomy. To provide added value in the diagnosis, treatment planning, and follow-up of mandibular fractures, radiologists should be aware of these concepts. Knowledge of the techniques commonly used to achieve occlusal and anatomic reduction and of the rationale behind the range of available treatment options for different injury patterns-from isolated and nondisplaced fractures to multisite and comminuted fractures-also is essential. This article focuses on the use of multidetector CT for pre- and postoperative evaluation of mandibular fractures and outlines fundamental concepts of diagnosis and management-beginning with an explanation of common fracture patterns and their biomechanical underpinnings, and followed by a review of the common postoperative appearances of these fractures after semirigid and rigid fixation procedures. Specific considerations regarding fractures in different regions of the tooth-bearing and non-tooth-bearing mandible and the unique issues pertaining to the edentulous atrophic mandible are reviewed, and key features that distinguish major from minor complications are described. (©)RSNA, 2016.

Efficacy of Electronic Foramen Locators in Controlling Root Canal Working Length during Rotary Instrumentation.

The present study evaluated the efficacy of electronic foramen locators (EFLs) to control root canal working length during rotary instrumentation and to assess possible reliability variations of different working lengths. Forty-eight human mandibular bicuspids were randomly divided in 2 groups according to the used device, Root ZX II (RZX) and Propex II (PRO). They were further subdivided in 2 subgroups according to the root canal preparation level (0.0 and -1.0). Preparation was performed with the Protaper rotary system using a crown-down technique. RZX was employed on its automatic auto-reverse mode (AAR) and PRO was used with the MPAS-10R contra-angle to monitor the preparation. The last used file (F3) was fixed, and the apical portion of the teeth was worn buccolingually, allowing to measure the extent between the file tip and the apical foramen (AF). The precision values of 0.0 mm and -1.0 mm were 100% and 0.0% for RZX, and 100% and 66.7% for PRO, respectively, with a range of ±0.5 mm. Statistical analysis showed no differences between the groups at 0.0 mm. However, at -1.0 mm, RZX showed the poorest results (0.96±0.11 mm), followed by PRO (0.43±0.23 mm). The difference between RZX and PRO was statistically significant. The EFLs were precise in maintaining the working length during rotary preparation when reaching the AF, but when their penetration was limited, both devices showed decreased precision; the RZX AAR failed in all instances.

Efficacy of Electronic Foramen Locators in Controlling Root Canal Working Length during Rotary Instrumentation

Abstract: The present study evaluated the efficacy of electronic foramen locators (EFLs) to control root canal working length during rotary instrumentation and to assess possible reliability variations of different working lengths. Forty-eight human mandibular bicuspids were randomly divided in 2 groups according to the used device, Root ZX II (RZX) and Propex II (PRO). They were further subdivided in 2 subgroups according to the root canal preparation level (0.0 and -1.0). Preparation was performed with the Protaper rotary system using a crown-down technique. RZX was employed on its automatic auto-reverse mode (AAR) and PRO was used with the MPAS-10R contra-angle to monitor the preparation. The last used file (F3) was fixed, and the apical portion of the teeth was worn buccolingually, allowing to measure the extent between the file tip and the apical foramen (AF). The precision values of 0.0 mm and -1.0 mm were 100% and 0.0% for RZX, and 100% and 66.7% for PRO, respectively, with a range of ±0.5 mm. Statistical analysis showed no differences between the groups at 0.0 mm. However, at -1.0 mm, RZX showed the poorest results (0.96±0.11 mm), followed by PRO (0.43±0.23 mm). The difference between RZX and PRO was statistically significant. The EFLs were precise in maintaining the working length during rotary preparation when reaching the AF, but when their penetration was limited, both devices showed decreased precision; the RZX AAR failed in all instances.

Resumo: O presente estudo avaliou a eficiência de localizadores eletrônicos foraminais (LEFs) em controlar o limite apical de instrumentação durante o preparo com instrumentos rotatórios. Adicionalmente, determinou-se possíveis variações quando do emprego de diferentes comprimentos de trabalho. Quarenta e oito pré-molares inferiores humanos foram randomicamente divididos em 2 grupos de acordo com o aparelho empregado, Root ZX II (RZX) e Propex II (PRO). Em seguida foram subdivididos em 2 subgrupos em função do limite de preparo (0,0 e -1,0 mm). O preparo dos canais foi realizado com o sistema Protaper em sentido coroa-ápice. O RZX foi utilizando em sua função auto-reverso automático (ARA) e o PRO associado ao contra-angulo MPAS-10R, foi empregado como ferramenta de monitoramento durante o preparo. O último instrumento utilizado (F3) foi fixado em posição, após o que a porção apical dos dentes foi desgastada permitindo a determinação da distância entre a ponta dos instrumentos e o forame apical (FA). A precisão a 0,0 mm e -1,0 mm foi de 100% e 0,0% para o RZX, e de 100% e 66,7% para o PRO, respectivamente, considerando uma margem de ±0,05 mm. A análise estatística não encontrou diferenças entre os grupos a 0,0 mm, todavia, a -1,0 mm, o RZX ofereceu os piores resultados (0,96±0,11 mm), seguido do PRO (0,43±0,23 mm). Esta diferença foi estatisticamente significante. Os LEFs foram precisos na manutenção do comprimento de trabalho durante o preparo rotatório quando se atingiu o FA, todavia, quando esta penetração foi limitada, ambos os aparelhos perderam em precisão; o sistema ARA do RZX falhou em todos os casos.

Suicide ideation and bullying among US adolescents: examining the intersections of sexual orientation, gender, and race/ethnicity.

OBJECTIVES: We examined how race/ethnicity, gender, and sexual orientation shape adolescents' likelihood of being bullied and vulnerability to suicide ideation. METHODS: We analyzed pooled data from the 2009 and 2011 Youth Risk Behavior Surveys (n = 75 344) to assess race/ethnicity, gender, and sexual orientation variation in being bullied and suicide ideation. RESULTS: White and Hispanic gay and bisexual males, White lesbian and bisexual females, and Hispanic bisexual females were more likely to be bullied than were White heterosexual adolescents. Black lesbian, gay, and bisexual youths' vulnerability to being bullied was not significantly different from that of White heterosexual youths. Black and Hispanic heterosexual youths were less likely to be bullied than were White heterosexual youths. Despite differences in the likelihood of being bullied, sexual minority youths were more likely to report suicide ideation, regardless of their race/ethnicity, their gender, or whether they have been bullied. CONCLUSIONS: Future research should examine how adolescents' intersecting identities shape their experience of victimization and suicidality. School personnel should develop antibullying and antihomophobia policies in response to the disproportionate risk of being bullied and reporting suicidality among sexual minority youths.

Time-based lateral hygroscopic expansion of a water-expandable endodontic obturation point.

OBJECTIVES: This study compared the time-based lateral expansion of two sizes and two batches of water-expandable obturation points (CPoint, EndoTechnologies, LLC) and a similar-sized gutta-percha point (control) at various distances from the point apex: 5, 10, and 15mm. METHODS: Two batches of sizes 25 and 40 (0.06 taper) CPoints and a single lot of size 40 (0.06 taper) gutta-percha were tested (N=5). Points were fixed to the bottom of a Petri dish, and digital images of each point location were obtained under 50× magnification, which also captured a calibrated linear scale reticule. After imaging each dry cone location, 10mL of water was added, and images were obtained at various time points: 20 and 40min, 1, 2, 3, 4, 5, 6, 7, 8, and 24h. Between measurements, dishes were stored at 37°C. Side-to-side dimension of each point was determined using imaging software RESULTS: No significant differences (p>0.05) in lateral dimension at each tip distance between batches of similar-sized CPoint samples were found (2-tailed unpaired Student's t-test). Changes in CPoint dimension were significantly higher (p<0.05) for both sizes at each tip distance after 20min of water immersion (one-factor repeated-measures ANOVA; Tukey test). Gutta-percha did not significantly change from the dry value during water immersion (p>0.05). CONCLUSIONS: When exposed to water, the lateral expansion of a new hydrophilic endodontic obturation point significantly increases in dimension within 20min, whereas a conventional gutta-percha point does not.

In Vitro biocompatibility evaluation of a root canal filling material that expands on water sorption.

INTRODUCTION: CPoint is a polymeric endodontic point that takes advantage of water-induced, non-isotropic radial expansion to adapt to canal irregularities. This study evaluated the effects of CPoint on the viability and mineralization potential of odontoblast-like cells. METHODS: The biocompatibility of CPoint and commercially available gutta-percha points was evaluated by using a rat odontoblast-like cell line (MDPC-23). Cell viability was evaluated with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometry, and confocal laser scanning microscopy. The mineralization potential of MDPC-23 cells, in the presence of the root-filling materials, was evaluated by examining the changes in osteogenic gene marker expression (quantitative real-time polymerase chain reaction), alkaline phosphatase activity, alizarin red S assay, and transmission electron microscopy. RESULTS: CPoint showed higher initial cytotoxicity compared with gutta-percha and Teflon (P < .05), which became nonsignificant after 4 immersion cycles. Significant differences were also found between eluents from CPoint and gutta-percha at 1:1 concentration (P < .05) but not at 1:10 or 1:100 concentration. Both materials induced minimal apoptosis-induced alteration in plasma membrane permeability, as evidenced by flow cytometry and confocal laser scanning microscopy. Compared with the Teflon negative control, CPoint and gutta-percha groups showed up-regulation of most osteogenic gene markers except for dentin sialophosphoprotein, which was down-regulated. Alkaline phosphatase activity and alizarin red assay for CPoint and gutta-percha were both significantly higher than for Teflon but not significantly different from each other (P > .05). Transmission electron microscopy showed discrete nodular electron-dense mineralization foci in all 3 groups. CONCLUSIONS: The in vitro biocompatibility of CPoint is comparable to gutta-percha with minimal adverse effects on osteogenesis after elution of potentially toxic components.

Essentials of maxillofacial cone beam computed tomography.

Cone beam computed tomography (CBCT) is a diagnostic imaging modality that has shown rapid adoption in clinical dental practice over the past 10 years. CBCT images provide high quality, accurate 3-dimensional (3D) representations of the osseous elements of the maxillofacial skeleton. The purpose of this article is to provide (1) an introduction to maxillofacial CBCT technology, (2) an understanding of the relative patient radiation dose, and (3) to underline the appropriate use of CBCTas a diagnostic imaging modality with specific clinical applications.

Implementing safe routes to school: application for the socioecological model and issues to consider.

The newly established national Safe Routes to School (SRTS) program has the potential to positively influence individuals, communities, and the environment regardless of race, ethnicity, or socioeconomic status. Many communities are applying their interest in physical activity promotion toward creating policies and programs to encourage active travel, though many barriers exist. SRTS legislation provides funds to address some of the barriers and improve the ability of students to safely walk and bicycle to school. SRTS requires that 70% to 90% of the funds be used for infrastructure projects (i.e., engineering treatments, such as sidewalk construction), and 10% to 30% for noninfrastructure activities, such as education, encouragement, and enforcement. The socioecological model (SEM) is widely used in public health and includes five levels of influence on behavior, from individual to public policy. Application of the SEM to SRTS provides a framework for a comprehensive approach to improve active travel to school.

Use of cone beam computed tomography in endodontics.

Cone Beam Computed Tomography (CBCT) is a diagnostic imaging modality that provides high-quality, accurate three-dimensional (3D) representations of the osseous elements of the maxillofacial skeleton. CBCT systems are available that provide small field of view images at low dose with sufficient spatial resolution for applications in endodontic diagnosis, treatment guidance, and posttreatment evaluation. This article provides a literature review and pictorial demonstration of CBCT as an imaging adjunct for endodontics.

Pounds off with empowerment (POWER): a clinical trial of weight management strategies for black and white adults with diabetes who live in medically underserved rural communities.

OBJECTIVES: We evaluated lifestyle interventions for diabetic persons who live in rural communities. METHODS: We conducted a 12-month randomized clinical trial (n = 152) of "intensive-lifestyle" (modeled after the NIH Diabetes Prevention Program) and "reimbursable-lifestyle" (intensive-lifestyle intervention delivered in the time allotted for Medicare reimbursement for diabetes education related to nutrition and physical activity) interventions with usual care as a control. RESULTS: Modest weight loss occurred by 6 months among intensive-lifestyle participants and was greater than the weight loss among usual-care participants (2.6 kg vs 0.4 kg, P<.01). At 12 months, a greater proportion of intensive-lifestyle participants had lost 2 kg or more than usual-care participants (49% vs 25%, P<.05). No differences in weight change were observed between reimbursable-lifestyle and usual-care participants. Glycated hemoglobin was reduced among all groups (P<.05) but was not different between groups. CONCLUSIONS: Improvement in both weight and glycemia was attainable by lifestyle interventions designed for persons who had type 2 diabetes and lived in rural communities.