Two-Dimensional Radiographs and Cone-beam Computed Tomography Assessment of Concentrated Growth Factor and Platelet-Rich Fibrin Scaffolds in Regenerative Endodontic Treatment of Immature Incisors with Periapical Radiolucency: A Randomized Clinical Trial.

INTRODUCTION: The primary aim of this study was to compare the radiographic changes of immature incisors with periapical radiolucency after treatment with platelet-rich fibrin (PRF) and concentrated growth factor (CGF) platelet concentrate scaffolds as well as assessment of the clinical success rate over 12 months. The secondary aim was to monitor the radiographic changes in terms of reduction of periapical lesion diameter (PALD), root dentine thickness (RDT), root length (RL), and apical foramen width (AFW). The tertiary aim was to assess and pulp responses, after 12 months. METHODS: Fifty six children with seventy necrotic, single-rooted maxillary incisors with periapical radiolucency were treated with either CGF or PRF scaffolds (35 teeth per group). Two patients with 4 teeth (2 teeth in each group) failed to attain the follow-up recalls. Radiographic changes in terms of reduction of PALD, RDT, RL, and AFW were monitored using a 2-dimensional (2D) radiograph and cone-beam computed tomography (CBCT) scan. The clinical performance of teeth receiving both scaffolds was assessed after 6 and 12 months. Categorical and continuous data were analyzed using the chi-square test and the t test, respectively. The time and group effects on the means of different radiographic dimensions were tested using the general linear model. Bland-Altman plots were used to assess the level of agreement between the 2D radiographs and CBCT. The level of significance was defined at 0.05 and a 95% confidence interval. RESULTS: The means of PALD and RL showed significant enhancement in the CGF group compared to the PRF group (P < .05). While the difference between the 2 scaffolds in terms of RDT and AFW was not significant (P > .05). The findings of the 2D radiograph and CBCT were consistent. Clinically, both scaffold success rates were similar (93.9%) over the follow-up intervals. The influence of study independent variables had no significant effect on the success of the regenerative endodontic procedures outcome (P > .05). There was no significant difference in the positive pulp responses to the thermal and electric pulp tests after one year of treatment (P > .05). CONCLUSIONS: According to the short-term follow-up, PRF and CGF were successful in treating immature teeth with periapical radiolucency by regenerative endodontics. Both scaffold systems induced periapical healing and root lengthening with significant superiority of CGF.

Comparative assessment of dentin removal following hand and rotary instrumentation in primary molars using cone-beam computed tomography.

OBJECTIVE: Pediatric endodontics has witnessed many advances in recent years, thus facilitating a faster and efficient treatment option in root canal therapy in children. This in vitro evaluation aims to determine the amount of dentin removal in primary mandibular first and second molars instrumented with hand and rotary files using cone-beam computed tomography (CBCT). MATERIALS AND METHOD: Sixty primary mandibular molars were divided into two groups: Group I was prepared by manual instrumentation using K-type files and Group II was prepared with rotary instrumentation using 0.04 Hero Shaper Classics. Both these groups were further divided into two subgroups, namely (a) primary mandibular first molar and (b) primary mandibular second molar. All the root canals were prepared up to size 30 using the stepback technique. They were mounted on silicone-based impression material and subjected to CBCT scans for the evaluation of dentin removal before and after instrumentation. Dentin removal was calculated by superimposing images using the InVivo 5.1 Anatomage software. Data were statistically analyzed using independent samples t- test. RESULTS: An average amount of dentin removed was found to be significantly higher in manual instrumentation compared to rotary instrumentation in both primary mandibular first and second molars (P < 0.001). CONCLUSIONS: Rotary technique serves as an efficient alternative to the traditional manual instrumentation by overcoming its shortcomings in terms of conservation of the remaining dentin thickness and the time required for its preparation.

Reliability of upper airway assessment using CBCT.

Background: Upper airway analysis is an often-cited use of CBCT imaging by orthodontists; however, the reliability of airway measurements using this technology is not fully established. Objective: To determine the intra-examiner and inter-examiner reliability of the complete process of volumetric and cross-sectional area assessments of the upper airway using CBCT imaging. Materials and Methods: Six examiners of varying levels of education and clinical experience performed the steps necessary for airway analysis, including manual orientation, slice and threshold selection and measured nasopharyngeal, oropharyngeal, hypopharyngeal and total upper pharyngeal airway volumes in addition to minimum cross-sectional area on the CBCT images of 10 patients. All measurements were repeated after 4-weeks. Intra- and inter-examiner reliability was calculated using ICC and 95% CI. Results: Threshold selection showed poor intra- and poor inter-examiner reliability, whereas minimum cross-sectional area showed moderate intra- and poor inter-examiner reliability. Intra-examiner reliability of volumetric measurements varied based on the region assessed with ICC ranging from 0.747 to 0.976, and was worst for hypopharynx and best for the oropharynx. Inter-examiner reliability of volume measurements was generally lower, with ICC ranging from 0.175 to 0.945, and was worst for nasopharynx and best for the oropharynx. Conclusions: This study, for the first time, assessed the reliability of upper airway analysis with CBCT when all steps of image processing and measurement are performed by each examiner. Reliability improved with examiner experience, though was generally low for the hypopharynx and nasopharynx volumes and overall minimal cross-sectional area. The oropharyngeal volume was the only parameter to have excellent intra- and inter-examiner reliability.

A novel electron-microscopic method for measurement of mineral content in enamel lesions.

OBJECTIVE: To assess Scanning Electron Microscopy in Back-Scattered Emission mode (BSE-SEM) for measurement of lesion mineral content as a function of depth. Direct comparison is made with Transverse Micro-Radiography (TMR) and Surface Micro-Hardness (SMH) on carious and erosive lesions. DESIGN: Caries lesions prepared from sound bovine enamel at 37 °C and pH 4.6 in unsaturated (7d) or part-saturated (8d, 4.1 mM Ca2+, 8 mM Pi) lactic acid /methyl cellulose gel system, followed by TMR analysis. Erosive lesions prepared from sound bovine enamel (1% citric acid, pH3.8, room temperature) for 5, 10, 15 or 20 min at n = 10 per treatment group. SMH readings (Vickers diamond, 1.9 N, 20 s) were taken from acid-treated and reference areas of each sample. BSE-SEM performed on polished cross-sections of lesioned samples (Jeol JSM6490LV SEM; high vacuum, 10 keV beam voltage, magnification x500 with constant working distance of 10 mm). Under identical SEM conditions, polished standards i.e. MgF2, alumina, Mg, Al and Si provided a calibration plot of BSE-SEM signal vs. atomic number (z¯). Mineral content vs. depth plots were derived from the cross-sectional BSE-SEM data. RESULTS: Cross-sectional BSE-SEM images clearly differentiate between caries and erosive lesions. Comparison of caries lesion mineral loss from BSE-SEM with TMR data showed good correlation (R2 = 0.98). Similarly, comparison of BSE-SEM data from erosive lesions showed good correlation (R2 = 0.99) with hardness loss data from SMH. CONCLUSION: BSE-SEM provides a relatively rapid and cost-effective method for the assessment of mineral content in demineralised tooth enamel and is applicable to both caries and erosive lesions.

Cone Beam Computed Tomography.

In the last several decades, the need for 3D images in dentistry have developed. Computerized tomography was first introduced mainly with the advent of implantology, but its use remained limited to a small number of specialists, due to its indications, access and dose radiation. In the late 90's, a new technology using a cone-shaped beam and a reciprocating detector, which rotates around the patient 360 degrees and acquires projected data in a single rotation, namely the cone beam computerized tomography (CBCT), invaded dentistry, making the perception of 3D easily acceptable to dentists and their patients.

Reliability of three-dimensional anterior cranial base superimposition methods for assessment of overall hard tissue changes: A systematic review.

OBJECTIVE: The purpose of this systematic review was to synthesize the available literature concerning the reliability of three-dimensional superimposition methods when assessing changes in craniofacial hard tissues. MATERIALS AND METHODS: Four electronic databases were searched. Two authors independently reviewed potentially relevant articles for eligibility. Clinical trials, cohort, case-control, and cross-sectional studies that evaluated the reliability of three-dimensional superimposition methods on the anterior cranial base were included. RESULTS: Six studies fulfilled the inclusion criteria. Four studies used the voxel-based registration method, one used the landmark-based method and one used the surface-based method. Regarding reliability, the voxel-based studies showed on average a difference of 0.5 mm or less between images. The optimized analysis using a six-point correction algorithm in the landmark-based method showed 1.24 mm magnitude of error between images. CONCLUSIONS: Although reliability appears to be adequate, the small sample size and high risk of bias among studies make available evidence still insufficient to draw strong conclusions.

Assessment of the primary stability of root analog zirconia implants designed using cone beam computed tomography software by means of the Periotest® device: An ex vivo study. A preliminary report.

BACKGROUND: The implant primary stability is a fundamental prerequisite for a success of osseointegration process which determines the prosthetic reconstruction time. OBJECTIVES: The aim of the present study was to assess the quality and precision of modern conical bone computer tomography (CBCT) software in preparing root analog zirconia implants (RAZIs) by measuring its primary stability by means of the Periotest device. MATERIAL AND METHODS: Thirteen pig jaws with proper erupted first premolar (P1) teeth were used in the study. The CBCT examination was conducted in the area of the P1 tooth in each mandible. The 3-dimensional (3D) view of each tooth was designed from CBCT scan. The created 3D images were used to prepare root analog zirconia implants milled from a medical-grade zirconia block by means of laboratory milling. The RAZIs and titanium implants were placed into an alveolar socket after the tooth had been removed. The primary stability of the teeth before their extraction (G1), RAZIs (G2) and titanium implants (G3) were checked by Periotest devices. RESULTS: The mean results in PTV were: 15.9, 3.35, 12.7 for G1, G2 and G3 group, respectively. RAZIs during immediate loading achieved a significantly higher primary stability (lower Periotest value) as compared to the teeth and implants. CONCLUSIONS: The modern CBCT device allows us to design a precise image of an extracted tooth for the purpose of manufacturing a root analog implant. The additional feature of the surgical protocol using RAZI is the possibility of avoiding the augmentation procedure, which reduces the whole cost of the treatment.

Assessment of Root Resorption and Root Shape by Periapical and Panoramic Radiographs: A Comparative Study.

INTRODUCTION: One of the common findings encountered by the clinician at the end of orthodontic treatment is the apical root resorption. Root resorption occurs to various degrees. A severe form of root resorption is characterized by shortening of root for more than 4 mm or more than one-third of the total tooth length. A low incidence rate of resorption is observed based on radiographic findings for the diagnosis of root resorption, panoramic radiography, and periapical radiography. Hence, we evaluated the accuracy of panoramic radiographic films for assessing the root resorption in comparison with the periapical films. MATERIALS AND METHODS: This study included the assessment of all the cases in which pre- and post-treatment radiographs were available for analysis of the assessment of the amount of root resorption. Complete records of 80 patients were analyzed. Examination of a total of 900 teeth was done. Mean age of the patients in this study was 21 years ranging from 11 to 38 years. The majority of the patients in the present study were females. All the treatments were carried out by registered experienced orthodontists having minimum experience of more than 10 years. All the cases were divided into two study groups. Group I comprised panoramic radiographic findings, while group II consisted of periapical radiographic findings. For the measurement of crown portion, root portion, and the complete root length, magnification loops of over 100 powers with parallax correction with inbuilt grids were used. Assessment of the tooth length and the crown length was done by the same observers. All the results were analyzed by Statistical Package for the Social Sciences software version 6.0. RESULTS: Maximum amount of root resorption was observed in case of maxillary central incisors and canines among group I and II cases respectively. However, nonsignificant difference was obtained while comparing the mean root resorption in relation to maxillary incisors and canines among the two study groups. While comparing the overall value of root resorption among the two study groups, a significant difference was obtained. The maximum value of tooth length in both the groups was observed in cases of maxillary canines. Significant differences were observed while comparing the tooth length of various teeth among the two study groups. Among the deviated forms of root shape, dilacera-tion was the most common form of root shape detected in both the study groups. CONCLUSION: Periapical radiographs are more efficient in the assessment of the shape and resorption of the root. CLINICAL SIGNIFICANCE: Thorough evaluation of periapical radiographs is necessary for detection of even minute levels of root resorption.

Assessing Bone Type of Implant Recipient Sites by Stereomicroscopic Observation of Bone Core Specimens: A Comparison With the Assessment Using Dental Radiography.

BACKGROUND: The aim of the study is to determine if bone quality evaluation of surgically obtained bone core specimens using a stereomicroscope is reliable for determining bone quality at implant recipient sites. METHODS: Bone quality was presurgically assessed in 122 edentulous ridges obtained from 62 patients using periapical radiographs and categorized according to the Lekholm and Zarb classification. During surgery, bone specimens were trephined, and bone types were immediately classified using a stereomicroscope. Microarchitectural characteristics of bone cores were evaluated after being scanned using microcomputed tomography (micro-CT). RESULTS: Bone types of implant sites categorized from radiography and stereomicroscope had statistically similar distribution but poor interrater agreement. Using micro-CT, maxillae and mandibles showed significant differences in microarchitectural characteristics of bone cores. Bone volume (BV), total volume (TV), and trabecular thickness (Tb.Th) increased, whereas bone surface density (BS/BV) and open porosity (Po.[Op]) decreased in mandibular bone cores compared with those in maxillary bone cores. Moreover, micro-CT values of BV/TV and Po.(Op) statistically correlated with bone types assessed by stereomicroscopy, particularly in mandibles (adjusted means of BV/TV of Type 2 to 4 versus Type 1 decreasing from -9.88%, -15.09%, -29.31%; those of Po.(Op) ranged from 9.77%, 15.06%, 29.52% in an upward trend). However, such correlations were not found in maxillae or when bone types were classified using periapical radiographs. CONCLUSIONS: Caution is needed when using presurgical periapical radiographs to predict bone quality at implant recipient sites. Surgically preserved bone core specimens, whenever obtainable, might offer additional information to accurately assess bone quality, particularly at mandibular implant sites.

Micro-computed Tomography Assessment of Dentinal Micro-cracks after Root Canal Preparation with TRUShape and Self-adjusting File Systems.

INTRODUCTION: The aim of the present study was to evaluate the percentage frequency of dentinal micro-cracks observed after root canal preparation with TRUShape and Self-Adjusting File (SAF) systems by means of micro-computed tomography imaging analysis. A conventional full-sequence rotary system (BioRace) and a single-file reciprocation system (Reciproc) were used as reference techniques for comparison because of their known assertive cutting efficiency. METHODS: Forty anatomically matched mandibular incisors were selected, scanned at a resolution of 14.25 µm, and assigned to 4 experimental groups (n = 10), according to the preparation protocol: TRUShape, SAF, BioRace, and Reciproc systems. After the experimental procedures, the specimens were scanned again, and the registered preoperative and postoperative cross-section images of the roots (n = 70,030) were screened to identify the presence of dentinal micro-cracks. RESULTS: Overall, dentinal defects were observed in 28,790 cross-section images (41.11%). In the TRUShape, SAF, BioRace, and Reciproc groups, dentinal micro-cracks were visualized in 56.47% (n = 9842), 42.38% (n = 7450), 32.90% (n = 5826), and 32.77% (n = 5672) of the slices, respectively. All dentinal defects observed in the postoperative data sets were already present in the corresponding preoperative images. CONCLUSIONS: None of the preparation systems induced the formation of new dentinal micro-cracks.

Virtual setup: application in orthodontic practice.

BACKGROUND: A plaster dental model is a patient's traditional three-dimensional (3D) record. If the dental crowns from a plaster model are separated and positioned in wax, this setup of the crowns can be used to simulate orthodontic treatment. The traditional way to make this dental setup requires significant time by the orthodontist and in the orthodontic lab. New developments in dentistry and orthodontics include the possibility of virtual setups. AIM: In this article, the differences between conventional setups with plaster models and virtual setups are discussed. METHODS: A clinical patient is described for whom two different setups were made and compared by model superimposition with Geomagic Qualify software. RESULTS: According to the literature and the results from this study, virtual setups and conventional setups with plaster models are equally accurate. CONCLUSION: Virtual setups present several advantages, e.g., digital storage, digital models cannot be damaged, the same model can undergo several treatment simulations, and communication between dental and surgical professionals and between dental professionals and patients is facilitated. Despite these advantages, considerable time and training are needed for dental professionals to master and adopt the general use of digital models and virtual setups in dentistry.

MRI vs. CT for orthodontic applications: comparison of two MRI protocols and three CT (multislice, cone-beam, industrial) technologies.

OBJECTIVES: To examine the relative usefulness and suitability of magnetic resonance imaging (MRI) in daily clinical practice as compared to various technologies of computed tomography (CT) in addressing questions of orthodontic interest. METHODS: Three blinded raters evaluated 2D slices and 3D reconstructions created from scans of two pig heads. Five imaging modalities were used, including three CT technologies-multislice (MSCT), cone-beam CT (CBCT), and industrial (µCT)-and two MRI protocols with different scan durations. Defined orthodontic parameters were rated one by one on the 2D slices and the 3D reconstructions, followed by final overall ratings for each modality. A mixed linear model was used for statistical analysis. RESULTS: Based on the 2D slices, the parameter of visualizing tooth-germ topography did not yield any significantly different ratings for MRI versus any of the CT scans. While some ratings for the other parameters did involve significant differences, how these should be interpreted depends greatly on the relevance of each parameter. Based on the 3D reconstructions, the only significant difference between technologies was noted for the parameter of visualizing root-surface morphology. Based on the final overall ratings, the imaging performance of the standard MRI protocol was noninferior to the performance of the three CT technologies. CONCLUSIONS: On comparing the imaging performance of MRI and CT scans, it becomes clear that MRI has a huge potential for applications in daily clinical practice. Given its additional benefits of a good contrast ratio and complete absence of ionizing radiation, further studies are needed to explore this clinical potential in greater detail.

CUSTOMISATION OF A MONTE CARLO DOSIMETRY TOOL FOR DENTAL CONE-BEAM CT SYSTEMS.

A versatile EGSnrc Monte Carlo (MC) framework, initially designed to explicitly simulate X-ray tubes and record the output data into phase space data files, was modified towards dental cone-beam computed tomography (CBCT) dosimetric applications by introducing equivalent sources. Half value layer (HVL) measurements were conducted to specify protocol-specific energy spectra. Air kerma measurements were carried out with an ionisation chamber positioned against the X-ray tube to obtain the total filtration attenuation characteristics. The framework is applicable to bowtie and non-bowtie inherent filtrations, and it accounts for the anode heel effect and the total filtration of the tube housing. The code was adjusted to the Promax 3D Max (Planmeca, Helsinki, Finland) dental CBCT scanner. For each clinical protocol, calibration factors were produced to allow absolute MC dose calculations. The framework was validated by comparing MC calculated doses and measured doses in a cylindrical water phantom. Validation results demonstrate the reliability of the framework for dental CBCT dosimetry purposes.

Assessment of mandibular posterior regional landmarks using cone-beam computed tomography in dental implant surgery.

The aim of this study has been to evaluate and correlate the anatomical features of the posterior mandibular region (submandibular fossa depth, bone height and thickness, and mandibular canal corticalization) to improve accident prevention and allow safe planning in implantology. Four parasagittal sections of cone-beam computed tomography (CBCT) from 100 patients were bilaterally analyzed. Linear measurements of the submandibular fossa depth, bone height and thickness were performed. The submandibular fossa was also classified into non-influential undercuts and influential undercuts for implant placement. Mandibular canal corticalization was also evaluated and classified according to the visualization. Data on patient age and gender were also collected. Forty-one scans (41%) were from male patients, and 59 (59%) were from female patients. Patient age ranged between 18 and 84 years, with an average age of 51.37 years. The submandibular fossa depth and implant bone thickness had a significant effect on the variability of the sample (46.1% and 22.3%, respectively). The submandibular fossa depth was quite variable, and the highest values were observed in the posterior regions. In 18.27% of the cases, the presence of the fossa directly influenced implant placement, considering a bone height of 10mm (standard implant). A significant correlation was observed between fossa depth and bone thickness. Thus, greater attention should be paid to thick ridges; although thick ridges are favorable, they may be associated with deeper submandibular fossae. The mandibular canal was the most influential anatomical structure in the premolar region due to the reduced bone height in this region and the greater difficulty in viewing the canal, and the submandibular fossa was the most influential structure in the molar region due to lower bone height leading up to the fossa and the greater fossa depth in this region. Therefore, CBCT is an important tool for assessing the mandibular region and planning for safe implant installation in the posterior mandible. Furthermore, comprehensive evaluation of the characteristics of this region is necessary, as the variables - submandibular fossa depth, bone height and thickness, and mandibular canal corticalization - are related and must be considered together when planning.

3D reconstruction based on compressed-sensing (CS)-based framework by using a dental panoramic detector.

In this work, we propose a practical method that can combine the two functionalities of dental panoramic and cone-beam CT (CBCT) features in one by using a single panoramic detector. We implemented a CS-based reconstruction algorithm for the proposed method and performed a systematic simulation to demonstrate its viability for 3D dental X-ray imaging. We successfully reconstructed volumetric images of considerably high accuracy by using a panoramic detector having an active area of 198.4 mm × 6.4 mm and evaluated the reconstruction quality as a function of the pitch (p) and the angle step (Δθ). Our simulation results indicate that the CS-based reconstruction almost completely recovered the phantom structures, as in CBCT, for p≤2.0 and θ≤6°, indicating that it seems very promising for accurate image reconstruction even for large-pitch and few-view data. We expect the proposed method to be applicable to developing a cost-effective, volumetric dental X-ray imaging system.

Assessment of upper airways measurements in patients with mandibular skeletal Class II malocclusion.

OBJECTIVE: Mandibular Class II malocclusions seem to interfere in upper airways measurements. The aim of this study was to assess the upper airways measurements of patients with skeletal Class II malocclusion in order to investigate the association between these measurements and the position and length of the mandible as well as mandibular growth trend, comparing the Class II group with a Class I one. METHODS: A total of 80 lateral cephalograms from 80 individuals aged between 10 and 17 years old were assessed. Forty radiographs of Class I malocclusion individuals were matched by age with forty radiographs of individuals with mandibular Class II malocclusion. McNamara Jr., Ricketts, Downs and Jarabak's measurements were used for cephalometric evaluation. Data were submitted to descriptive and inferential statistical analysis by means of SPSS 20.0 statistical package. Student's t-test, Pearson correlation and intraclass correlation coefficient were used. A 95% confidence interval and 5% significance level were adopted to interpret the results. RESULTS: There were differences between groups. Oropharynx and nasopharynx sizes as well as mandibular position and length were found to be reduced in Class II individuals. There was a statistically significant positive correlation between the size of the oropharynx and Xi-Pm, Co-Gn and SNB measurements. In addition, the size of the nasopharynx was found to be correlated with Xi-Pm, Co-Gn, facial depth, SNB, facial axis and FMA. CONCLUSION: Individuals with mandibular Class II malocclusion were shown to have upper airways measurements diminished. There was a correlation between mandibular length and position and the size of oropharynx and nasopharynx.

Assessment of upper airways measurements in patients with mandibular skeletal Class II malocclusion

Objective: Mandibular Class II malocclusions seem to interfere in upper airways measurements. The aim of this study was to assess the upper airways measurements of patients with skeletal Class II malocclusion in order to investigate the association between these measurements and the position and length of the mandible as well as mandibular growth trend, comparing the Class II group with a Class I one.Methods:A total of 80 lateral cephalograms from 80 individuals aged between 10 and 17 years old were assessed. Forty radiographs of Class I malocclusion individuals were matched by age with forty radiographs of individuals with mandibular Class II malocclusion. McNamara Jr., Ricketts, Downs and Jarabak's measurements were used for cephalometric evaluation. Data were submitted to descriptive and inferential statistical analysis by means of SPSS 20.0 statistical package. Student's t-test, Pearson correlation and intraclass correlation coefficient were used. A 95% confidence interval and 5% significance level were adopted to interpret the results.Results:There were differences between groups. Oropharynx and nasopharynx sizes as well as mandibular position and length were found to be reduced in Class II individuals. There was a statistically significant positive correlation between the size of the oropharynx and Xi-Pm, Co-Gn and SNB measurements. In addition, the size of the nasopharynx was found to be correlated with Xi-Pm, Co-Gn, facial depth, SNB, facial axis and FMA.Conclusion: Individuals with mandibular Class II malocclusion were shown to have upper airways measurements diminished. There was a correlation between mandibular length and position and the size of oropharynx and nasopharynx.

Introdução: as más oclusões de Classe II mandibulares parecem interferir nas dimensões das vias aéreas superiores. Assim, o objetivo do presente estudo foi avaliar as vias aéreas superiores de pacientes com Classe II esquelética, verificando a associação entre essas dimensões e a posição mandibular, o comprimento mandibular e a tendência de crescimento, comparando-os com um grupo pareado de pacientes com Classe I.Métodos: foram avaliadas 80 telerradiografias de perfil de 80 pacientes com 10 a 17 anos de idade, sendo 40 com má oclusão de Classe I e 40 com Classe II mandibular, pareados por idade. Para a avaliação cefalométrica, foram utilizadas medidas de McNamara Jr, Ricketts, Downs e Jarabak. Os dados foram submetidos à análise estatística descritiva e inferencial, por meio dosoftware SPSS 20.0, utilizando-se os testest de Student, coeficiente de correlação de Pearson e coeficiente de correlação intraclasse. Para interpretação dos resultados, adotou-se um intervalo de confiança de 95% e nível de significância de 5%.Resultados: houve diferença entre os grupos, e as medidas da orofaringe e nasofaringe foram menores no grupo de Classe II, assim como as medidas de comprimento e posição mandibular. Houve correlação positiva estatisticamente significativa entre a orofaringe e as medidas Xi-Pm, Co-Gn e SNB; já a nasofaringe apresentou correlação com as medidas Xi-Pm, Co-Gn, profundidade facial, SNB, eixo facial e FMA.Conclusão: indivíduos portadores de Classe II mandibular apresentaram as medidas das vias aéreas superiores diminuídas. Observou-se uma correlação entre o comprimento mandibular e a posição mandibular e as dimensões da orofaringe e da nasofaringe.

Radiologic Assessment of Periapical Health: Comparison of 3 Different Index Systems.

INTRODUCTION: The aim of this study was to evaluate observer variations and observer reproducibility in the interpretation of periapical health using the Strindberg system, the periapical index (PAI), and the probability index for radiologic assessment of periapical health. METHODS: Four observers read digital periapical images to evaluate the periapical health of 200 root-filled teeth. Each observer evaluated a tooth twice by using the Strindberg system, twice by using the PAI, and twice by using the probability index. Each observation session was held at 1-month intervals. Three scores were used for the evaluations conducted by using the Strindberg system. Both the PAI and the probability index were considered on 5-point scales and were also dichotomized. SPSS for Windows 15.0 software (SPSS Inc, Chicago, IL) was used for data analysis, and intra- and interobserver agreements were described by using kappa statistics. RESULTS: The average kappa values of intra- and interobserver agreement calculated for the Strindberg system were 0.53 and 0.36, respectively. The corresponding average kappa values were calculated as 0.48 and 0.39 for the PAI and 0.45 and 0.30 for the probability index. The highest mean proportion values of intra- and interobserver agreement were observed for the dichotomization of the PAI (88.9% and 87.0%, respectively) followed by the dichotomization of the probability index (86.8% and 82.9%, respectively). CONCLUSIONS: The Strindberg system has lower intraobserver variation compared with the PAI and the probability index, whereas PAI has lower interobserver variation compared with the Strindberg system and the probability index. The dichotomization of the PAI and the probability index provided higher intra- and interobserver agreement values in the radiologic assessment of periapical health.

Reducing an already low dental diagnostic X-ray dose: does it make sense? Comparison of three cost-utility analysis methods used to assess two dental dose-reduction measures.

OBJECTIVES: To find a method that is suitable for providing an objective assessment of the cost effectiveness of a dose-reducing measure used for diagnostic dental X-ray exposures. METHODS: Three cost-utility analysis (CUA) methods were evaluated by comparing their assessments of two dose-reduction measures, a rectangular collimator and the combination of two devices that reduce the radiation dose received during orthodontic lateral cephalography. The following CUA methods were used: (1) the alpha value (AV), a monetary valuation of dose reduction used in the nuclear industry; (2) the value of a statistical life for valuation of the reduction in stochastic adverse effects; and (3) the time-for-time method, based on the postulate that risk reduction is effective when the number of years of life gained is more than the years that an average worker must work to earn the costs of the risk-reducing measure. The CUA methods were used to determine the minimum number of uses that was required for the dose-reducing device to be cost effective. The methods were assessed for coherence (are comparable results achieved for comparable countries?) and adaptability (can the method be adjusted for age and gender of specific patient groups?). RESULTS: The performance of the time-for-time method was superior to the other methods. Both types of dose-reduction devices tested were assessed as cost effective after a realistic number of uses with all three methods except low AVs. CONCLUSIONS: CUA for the methods of X-ray dose reduction can be performed to determine if investment in low dose reduction is cost effective. The time-for-time method proved to be a coherent and versatile method for performing CUA.