Influence of base designs on the manufacturing accuracy of vat-polymerized diagnostic casts using two different technologies.

STATEMENT OF PROBLEM: Diagnostic casts can incorporate different base designs and be manufactured using different vat-polymerization technologies. However, the influence of the interrelation between the base design and the 3D printing technology on the casts' final accuracy remains unclear. PURPOSE: The purpose of this in vitro study was to assess the influence of different base designs of 3D printed casts on the accuracy of 2 vat-polymerization technologies. MATERIAL AND METHODS: A digital maxillary cast was obtained and used to generate 3 different base designs: solid (S group), honeycombed (HC group), and hollow (H group). The HC and H groups were subdivided based on the wall thickness of the cast design, resulting in 2 subgroups with thicknesses of 1 mm (HC1 and H1) and 2 mm (HC2 and H2) (N=100, n=10). Eleven reference cubes were added to each specimen for subsequent measurements. Specimens were manufactured by using 2 vat-polymerization 3D printers: Nextdent 5100 (ND group) and Sonic Mini 4K (SM4K group) and a resin material suitable for both 3D printers (Nextdent Model 2.0). A coordinate measuring machine quantified the linear and 3-dimensional discrepancies between the digital cast and each reference specimen. Trueness was defined as the average absolute dimensional discrepancy between the virtual cast and the specimens produced through additive manufacturing (AM), while precision was delineated as the standard deviation in dimensional discrepancies between the digital cast and the AM specimens. The data were analyzed using the Kruskal-Wallis and Mann-Whitney U pairwise comparison tests (α=.05). RESULTS: For the NextDent group the trueness ranged from 21.83 µm to 28.35 µm, and the precision ranged from 17.82 µm to 37.70 µm. For the Phrozen group, the trueness ranged from 45.15 µm to 64.51 µm, and the precision ranged from 33.51 µm to 48.92 µm. The Kruskal-Wallis test showed significant differences on the x-, y-, and z-axes and in the 3D discrepancy (all P<.001). On the x-axis, the Mann-Whitney U test showed significant differences for the Phrozen group between the H-2 and H-1 groups (P=.001), H-2 and S groups (P<.001), and HC-2 and S groups (P=.012). On the y-axis, significant differences were found in the Phrozen group between the H-2 and H-1 groups (P=.001), the H-2 and S, H-1 and HC-1, and HC-1 and S groups (P<.001), the H-1 and HC-2 groups (P=.007), and the HC-2 and S groups (P=.009). The NextDent group exhibited significant differences, particularly among the HC-1 and H-2 groups (P=.004), H-1 (P=.020), and HC-2 (P=.001) groups; and on the z-axis significant differences were found in the Phrozen group between the H-2 and H-1 and S groups and the HC-2 group and H-1 and S groups (both P<.001). In the NextDent group, significant differences were found between the H-2 and HC-2 (P=.047) and HC-1 (P=.028) groups. For the 3D discrepancy analysis, significant differences were found in the Phrozen group between the H-2 and H-1 and S groups (P<.001), the H-1 and HC-2 groups (P=.001), the S and HC-1 and HC-2 groups (P<.001), and the H-1 and HC-1 groups (P=.002). In the NextDent group, significant differences were observed between the H-2 and HC-1 groups (P=.012). CONCLUSIONS: The accuracy of digital casts depends on the manufacturing trinomial and base design of the casts. The honeycomb and hollow based designs provided the highest accuracy in the NextDent and Phrozen groups respectively for the material polymer tested. All specimens fell in the clinically acceptable range.

OralImmunoAnalyser: a software tool for immunohistochemical assessment of oral leukoplakia using image segmentation and classification models.

Oral cancer ranks sixteenth amongst types of cancer by number of deaths. Many oral cancers are developed from potentially malignant disorders such as oral leukoplakia, whose most frequent predictor is the presence of epithelial dysplasia. Immunohistochemical staining using cell proliferation biomarkers such as ki67 is a complementary technique to improve the diagnosis and prognosis of oral leukoplakia. The cell counting of these images was traditionally done manually, which is time-consuming and not very reproducible due to intra- and inter-observer variability. The software presently available is not suitable for this task. This article presents the OralImmunoAnalyser software (registered by the University of Santiago de Compostela-USC), which combines automatic image processing with a friendly graphical user interface that allows investigators to oversee and easily correct the automatically recognized cells before quantification. OralImmunoAnalyser is able to count the number of cells in three staining levels and each epithelial layer. Operating in the daily work of the Odontology Faculty, it registered a sensitivity of 64.4% and specificity of 93% for automatic cell detection, with an accuracy of 79.8% for cell classification. Although expert supervision is needed before quantification, OIA reduces the expert analysis time by 56.5% compared to manual counting, avoiding mistakes because the user can check the cells counted. Hence, the SUS questionnaire reported a mean score of 80.9, which means that the system was perceived from good to excellent. OralImmunoAnalyser is accurate, trustworthy, and easy to use in daily practice in biomedical labs. The software, for Windows and Linux, with the images used in this study, can be downloaded from https://citius.usc.es/transferencia/software/oralimmunoanalyser for research purposes upon acceptance.

20 years of alveolar distraction: A systematic review of the literature

BACKGROUND: The Vertical Alveolar Distraction Osteogenesis (VADO) technique is an excellent solution for bone and soft tissue neoformation in areas in which there has been significant bone atrophy that hinders normal rehabilitation using dental implants. The goal of this systematic review is to analyze the most relevant articles published on VADO in the literature over the past 20 years. MATERIAL AND METHODS: The review was performed by using the keywords: "alveolar ridge", "distraction ostegenesis" and "dental implant". This search produced a total result of 240 articles. The clinical studies and cases reported in humans amounted to 113 articles, 18 articles referred to studies developed on animals and 33 review articles. The presentation of this systematic analysis follows the criteria described in the PRISMA declaration. RESULTS: 22 articles complied with the inclusion criteria and 7 articles more were added manually, reaching a total sample of 29 studies. Following the analysis of the studies, they were classified into 18 high-quality, 10 mediumquality and 1 low-quality study. Only 4 studies achieved a maximum score of 9 (according to NewCastle Ottawa Scale, NOS). CONCLUSIONS: VADO is a technique with greater potential in vertical gain. The performance of dental implants has a success and survival rate similar to dental implants placed on bones that are not subject to increase techniques

Survival study of leukoplakia malignant transformation in a region of northern Spain

BACKGROUND: Oral leukoplakia is the most common potentially malignant disorder (PMD) of the oral cavity. The objectives of this study are to determine the clinicopathologic features in a group of patients with oral leukoplakia of Northern Spain (Galicia), determining the factors associated to clinical risk and analyzing the malignant transformation of these patients. MATERIAL AND METHODS: We included 85 patients. We recorded sex and age, habits like alcohol and tobacco, size, clinical appearance, site, number of lesions, and presence or absence of dysplasia. We assess the association between risk factors and transformation and developed a logistic regression analysis. Finally we used the Kaplan-Meier and log-rank test for the survival analysis. RESULTS: 7 patients (8.2%) had malignant transformation. The mean follow-up of the patients was 4.13 years versus 5.58 years of those who developed carcinoma. Only location and initial dysplasia have a statistically significant relationship with malignant transformation, but when applied the long rank test only the presence of dysplasia remains statistically significant (P<0,026). Oral Cancer Free Survival was 81.9% (0.150) at 11 years for the group without dysplasia. CONCLUSIONS: We found that the presence of dysplasia is the only risk factor that is statistically related to the development of a carcinoma

A modified device for intraoral radiography to assess the distal osseous defects of mandibular second molar after impacted third molar surgery

PURPOSE: This article is to describe a modified device for intraoral radiography which was developed to obtain reproducible radiographic images for assessment of distal osseous defects of the mandibular second molar (2 Mm) after impacted third molar (3 Mm) surgery. MATERIALS AND METHODS: A commercial available alignment system for posterior region was modified by adding a reference gauge pin (millimetric) and threading a hollow acrylic cylinder at the ring of the radiographic positioner to attach the X-ray collimator. The design included customized resin acrylic stent for the occlusal surface of the 2Mm in maximum intercuspal position, individualizing the biteblock positioner. Periapical radiographs were taken before and after surgical extraction of 3 Mm, employing the radiographic technique of parallelism described by Kugelberg (1986) with this modified film holder and inserting the gauge pin on the deepest bone probing depth point. RESULTS: This technique permitted to obtain standardized periapical radiographs with a moderate to high resolution, repeatability, and accuracy. There was no difference between the measurements on the pre- and post-operative radiographs. This technique allowed better maintenance of the same geometric position compared with conventional one. The insertion of the gauge pin provided the same reference point and localized the deepest osseous defect on the two-dimensional radiographs. CONCLUSION: This technique allowed better reproducibility in posterior radiographic records (distal surface of 2 Mm) and more accurate measurements of radiographic bone level by the use of a millimetric pin.

Disóstosis cleidocraneal. Presentación de un caso clínico / Cleidocranial dysostosis. Report of a case

La disóstosis cleidocraneal es una entidad clínica descrita por Marie y Sainton en 1897. Se caracteriza por aplasia clavicular completa o incompleta, aumento del diámetro transversal del cráneo, osificación retardada de las suturas y fontanelas, malformaciones óseas, anomalías dentales y transmisión hereditaria. Estas características clínicas condicionan el aspecto extraoral de estos pacientes: braquicefálicos, con abombamiento frontal y parietal, puente nasal con dorso deprimido y ensanchado, hipertelorismo, surcos nasolabiales pronunciados y baja estatura. La deficiencia clavicular descrita contribuye al aspecto alargado del cuello y a la estrechez de hombros, y le permite al paciente la posibilidad de aproximar los hombros por delante del tórax. A nivel oral, las anomalías de los maxilares y de los dientes son casi constantes. Las principales características clínicas orales de este síndrome son la reabsorción retardada de las raíces de los dientes temporales, el retraso eruptivo de la dentición permanente, la localización ectópica y anormal morfología dentaria de los dientes definitivos, presencia de múltiples dientes retenidos fundamentalmente dientes supernumerarios, el desarrollo de quistes dentígeros alrededor de los molares no erupcionados, y el escaso desarrollo del maxilar superior. El desarrollo mandibular es normal, aunque en pacientes adultos se observa la falta de fusión de la sínfisis mandibular debido probablemente al generalizado retraso existente en el desarrollo y la osificación esqueléticos de estos pacientes. El tratamiento dental de estos pacientes es lento y dificultoso, requiriendo con frecuencia un tratamiento multidisciplinario. Se presenta el caso clínico de un paciente adulto diagnosticado de disóstosis cleidocraneal, y se exponen las características clínicas, diagnósticas y terapéuticas a nivel dentario y craneofacial más importantes de este síndrome (AU)