Dental Pieces Research Articles

Teeth osteometry as tool for studying social complexity: Evaluating white-tailed deer hunting sustainability at Nueva Esperanza, Colombia

Examining archaeological remains of animals may aid in understanding complex social interactions among pre-Hispanic societies and their access to protein sources. We study the agro-pottery groups that inhabited Sabana de Bogotá in Colombia during the Herrera (400 BC–200 AD), Early Muisca (200 AD–1000 AD) and Late Muisca (1000 AD–1600 AD) periods. White-tailed deer (Odocoileus virginianus; Zimmerman, 1780) was the most common protein in the diet of these communities. The relative abundance of white-tailed deer remains can be used as an index for the economies of pre-Hispanic societies. This study analyzes changes in prey proportion by age group to evaluate consumption sustainability. An osteometric analysis is used to determine the age of the deer. As entire jaws are infrequent in the archaeological record, this investigation proposes a methodology using measures of the height of the dental pieces that are more likely to be found in archaeological sites. We analyze 512 O. virginianus dental pieces obtained from the Nueva Esperanza site, and we present evidence of the three periods and a reference table that matches the height of each dental piece to the individual's age group. The osteometric analysis reveals that height measurements are a good indicator to establish the age class of each individual, which was assigned to one of four categories: infantile, young, adult, and old adult. The results suggest that deer hunting intensified as the population grew during the Early Muisca period; however, this did not entail resource scarcity.

Anatomical Considerations and Study of the Fractal Dimension around the Posterior Superior Alveolar Artery

The Posterior Superior Alveolar Artery (PSAA) provides vascular support to molars, gingiva, and maxillary sinus. A tear of the PSAA may cause profuse hemorrhages which may lead to complications at a surgical level. As such, it becomes crucial to anatomically analyse several features regarding the PSAA as well as the area surrounding it. In this paper, we are particularly interested in the study of the complexity of the periodontal tissue structure which appears close to the location of the PSAA. A total amount of 400 cone beam computed tomography (CBCT) scans (two per subject) were performed to explore the presence of the PSAA, the thickness of the Schneider’s membrane, and the existence of septa. Several parameters were evaluated including the location of the artery in the maxillary sinus, the distance from the PSAA to the alveolar ridge, the thickness of the membrane, the diameter of the cavities produced by the septa, and the fractal dimension of the trabecular tissue that surrounds the PSAA. They were found strong linear relationships between Distal and Central Measures (a Pearson’s R 2 = 0.9952 ), Mesial and Central Measures ( R 2 = 0.9950 ), and Distal and Mesial Measure ( R 2 = 0.997 ). We hypothesised that the loss of dental pieces would imply a distinct complexity of the trabecular tissue structure surrounding the PSAA. In this way, a p-value equal to 0.001 was provided by the Mann-Whitney test, which supports our hypothesis. Furthermore, the mean of the fractal dimensions of the group of edentulous patients (equal to 1.56 ) was found to be lower than the one of the group of non-edentulous patients (equal to 1.61 ) with small standard deviations in both cases. Our study suggests that accurate calculations of the fractal dimension combined with the use of CBCT do provide valuable information regarding the area that surrounds the PSAA.

Development of free binder zirconia-based pastes for the production of dental pieces by robocasting

The current work aims to develop high solid load zirconia pastes without organic binder additives, for the robocasting of dental structures. The effect of the amount of Dolapix CE64 dispersant on the stabilisation of zirconia aqueous suspensions was first tested. The determined optimal amount of dispersant was then used to produce pastes with zirconia concentration in the 80−90 wt% range. Pastes were further studied regarding rheological behaviour and printability. The most printable were used to produce parallelepiped blocks by robocasting; slip casting samples were also produced for comparison. Density, surface roughness, porosity, hardness and toughness of both types of samples were assessed after sintering. Finally, a model molar tooth was produced by robocasting and sintered. The most encouraging robocasting results were obtained using a paste with 0.5 wt% Dolapix CE64 and 88 wt% zirconia. The produced samples displayed 97.1 % of theoretical density, Vickers hardness of 1485 ± 32 and fracture toughness of 4.11 ± 0.09 MPa.m1/2 after sintering. Similar values were obtained for slip casting parts. A model molar tooth with adequate surface finishing was successfully obtained using the described processing parameters, together with a brushing treatment carried out in the green state. Attained results show that it is possible to build zirconia prosthetic dental structures with adequate morphological and mechanical properties by robocasting of binder free pastes. This opens an opportunity window for the cost-effective and environmentally friendly customized production of prosthetic dental structures by additive manufacturing.

Tribological performance of the pair human teeth vs 3D printed zirconia: An in vitro chewing simulation study

This study aims to evaluate the tribological performance of the pair human teeth/robocasted zirconia, with a special focus on the enamel wear mechanisms. Zirconia pieces produced by robocasting (RC) and unidirectional compression (UC) were compared in terms of crystalline structure, density, porosity, hardness and toughness. Chewing simulation tests were performed against human dental cusps. The cusps wear was quantified and the wear mechanisms identified. Although most of the properties of UC and RC samples are similar, differences were observed for surface roughness and porosity. Although the samples did not suffer wear, the antagonist cusps worn in a similar way. In conclusion, robocasting seems a promising technique to produce customized zirconia dental pieces, namely in what concerns the overall tribological behaviour.

Accuracy of Intraoral Digital Impression Systems in Restorative Dentistry: A Review of the Literature

Digital impresión allows the dentist to directly obtain the data of the dental pieces that neet to be rehabilitated, giving it greater precisión and thus eliminating the impression and manufacturing of the dental model, error-sensitive aspects of the clinical phase. The aim of this review is to identify the most accurate intraoral digital impression system and identifiy the factors that affect the accuracy in the restorative dentistry. Through a bibliographic review with search in PubMed and Embase databases, 153 articles were obtained, after qualitative evaluation they were included in the revisión 14 that met the inclusion and exclusion criteria. It was determined that the experience of the dentist, the convergence in the dental preparation and the cervical termination are decisive at the accuracy of the digital impression, however, the use or not of dust is not relevant. The Lava C.O.S., iTero and True definition are the most accurate always depending on the type of rehabilitation to be performed.

Caries en el primer molar definitivo en adolescentes de una institución educativa pública de la ciudad de Portoviejo.

El primer molar es el primero de la dentición definitiva en erupcionar, se lo considera más susceptible al ataque de caries, su destrucción, así como su pérdida repercute a más de la oclusión, en la calidad de vida; por ello se realizó un estudio descriptivo transversal aplicando una encuesta a 150 estudiantes de 12 a 14 años. Se identificó que la gran mayoría de adolescentes tiene cariado al menos un primer molar, siendo las inferiores las más afectadas. El estilo de vida en salud oral de los adolescentes relacionado con los hábitos dietéticos y prácticas de higiene oral no son saludables constituyéndose en el factor de riesgo para que estas piezas dentales estén afectadas por caries.

SAT-109 ELABORATION OF A TEXTURE-MODIFIED FOOD DIDACTIC TOOL FOR PATIENTS WITH END-STAGE KIDNEY DISEASE UNDERGOING HEMODIALYSIS IN GUANAJUATO, MEXICO, WHO HAVE MISSING TEETH

The role of an adequate food intake on the preservation of an optimal nutritional status in patients with chronic kidney disease (CKD) undergoing dialysis, has been well described and there is significant evidence sustaining that a poor nutritional status can be related to several diseases, such as protein energy wasting syndrome, sarcopenia, it has a strong association with increased risk of hospitalization, worse clinical outcomes and even mortality. In order to ensure an adequate nutritional status and considering oral feeding as the classic pathway, we found imperative the necessity to offer options to patients who have masticatory issues due to dental loss. CKD patients undergoing dialysis usually have multiple comorbidities like diabetes, hypertension, mineral and bone disorder, inflammation, malnutrition, protein energy wasting, uremia, etc., which combined with aging and poor hygiene could promote oral cavity problems as periodontitis, cavities, gum disease and dental loss. Dental loss affects nutritional status of CKD patients in dialysis by interfering with the right intake of nutritious food. While it is true that some patients usually modify the texture of their meals in order to make chewing easier, sometimes the resulting dishes contain higher amounts of liquids than those they should consume (e.g. soups and jelly), which makes controlling of daily liquid intake harder. Thus, we aimed to elaborate a texture-modified food didactic tool for patients with CKD under hemodialysis who have missing teeth. From previous evidence in clinical practice guidelines, systematic reviews and original papers about nutritional requirements, based on food-texture modifications useful for patients with dental issues or deglutition problems and given that some recommendations can be extrapolated for patients with masticatory problems, we elaborated a didactic tool for CKD under hemodialysis patients, with dental loss. Subsequently, pertinent adjustments for patients undergoing dialysis were made: adequate use of liquids, restriction on high sources of sodium, phosphorus and potassium, and the incorporation of protein supplements and specialized polymeric formulas. We elaborated a didactic tool, digital and printed version, where the food-texture modifications for CKD under hemodialysis patients are described: double cooking, dicing, mincing, shredding, grating, pureeing and shaking. An extra section was included, where we designed easy to chew preparations that incorporate protein supplements and specialized polymeric formulas. For each technique, we described the making process, lists of ingredients and foods that can be used, taking into account low sources of sodium, phosphorus and potassium, as well as products we recommend avoiding. We also developed suggestions based on the loss of dental pieces according to their masticatory function: incisives, canines, premolars, molars or a combination of them. As far as we know, this texture-modified food didactic tool is the first step to help chronic hemodialysis patients with missing teeth, to improve their intake using low sources of phosphorus, potassium and sodium and without using more liquids than those required, giving them supplemented easy to chew meals. The recommendations herein could be used for other dialysis therapies users and by healthcare providers.

Automatic computation of mandibular indices in dental panoramic radiographs for early osteoporosis detection

A new automatic method for detecting specific points and lines (straight and curves) in dental panoramic radiographies (orthopantomographies) is proposed, where the human knowledge is mapped to the automatic system. The goal is to compute relevant mandibular indices (Mandibular Cortical Width, Panoramic Mandibular Index, Mandibular Ratio, Mandibular Cortical Index) in order to detect the thinning and deterioration of the mandibular bone. Data can be stored for posterior massive analysis. Panoramic radiographies are intrinsically complex, including: artificial structures, unclear limits in bony structures, jawbones with irregular curvatures and intensity levels, irregular shapes and borders of the mental foramen, irregular teeth alignments or missing dental pieces. An intelligent sequence of linked imaging segmentation processes is proposed to cope with the above situations towards the design of the automatic segmentation, making the following contributions: (i) Fuzzy K-means classification for identifying artificial structures; (ii) adjust a tangent line to the lower border of the lower jawbone (lower cortex), based on texture analysis, grey scale dilation, binarization and labelling; (iii) identification of the mental foramen region and its centre, based on multi-thresholding, binarization, morphological operations and labelling; (iv) tracing a perpendicular line to the tangent passing through the centre of the mental foramen region and two parallel lines to the tangent, passing through borders on the mental foramen intersected by the perpendicular; (v) following the perpendicular line, a sweep is made moving up the tangent for detecting accumulation of binary points after applying adaptive filtering; (vi) detection of the lower mandible alveolar crest line based on the identification of inter-teeth gaps by saliency and interest points feature description. The performance of the proposed approach was quantitatively compared against the criteria of expert dentists, verifying also its validity with statistical studies based on the analysis of deterioration of bone structures with different levels of osteoporosis. All indices are computed inside two regions of interest, which tolerate flexibility in sizes and locations, making this process robust enough. The proposed approach provides an automatic procedure able to process with efficiency and reliability panoramic X-Ray images for early osteoporosis detection.

Exceptional source of liver abscess: 3 cases of oropharynx origin

Background: Pyogenic liver abscess is a rare entity, it is fatal when untreated. Its approach has been improved due to percutaneous drainage and better microbiological characterization. In our environment, the most common pathogens are Enterobacteriaceae. Our aim is to present 3 cases of liver abscess caused by unusual microorganisms, habitual commensals of the oropharynx. Material & Methods: Two men and a women was admitted to emergency service with a story of fever (>38.5ºC). Case 1: A 64-year-old man without other sintoms. US and CT scan was performed, showed focal subcapsular lesion in the VII-VI segment, hypoechoic with hyperechogenic areas suggestive of abscess. Abscess drainage was performed and positive culture was obtained for Haemophilus parainfluenzae. Case 2: A 57-year-old woman mujer de 57 with jaundice and coluria. CT scan reported multiple hepatic abscesses. Abscess drainage was performed with positive culture for Streptococcus intermedium. The orthopantomography study showed radicular remnants of 36 and 46, both with implants. Case 3: A 61-year-old man with abdominal pain. CT showed heterogeneous mass in liver segments VII and VIII with small cystic areas inside. Abscess drainage was performed with positive culture for Streptococcus intermedium. Orthopantomography showed septic foci associated with implants. Results: All three patients were admitted with antibiotic treatment and radiologic drainage. In two of them (cases 1 and 3) antibiotic treatment was not enough, therefore surgery was performed; while in case 2 the antibiotic treatment was adequate. In addition, cases 2 and 3 received surgical treatment by maxillofacial surgery to extract the dental pieces. Currently, patients are asymptomatic. Conclusions: Haemophilus parainfluenzae and Streptococcus intermedium are a uncommon cause of liver abscess. Without treatment, the mortality of the liver abscess is 100%. Early diagnosis and correctly isolate the pathogens are essential even more when we face something uncommon.

Corrosion of galvanic pairs of Co-Cr alloys with high-copper silver amalgam using Mansfeld formulas

ABSTRACT In the restoration of lost or damaged dental pieces, different alloys are frequently used, leaving the mouth exposed to electrical currents that circulate through saliva and dental fluids. In the present work, electrochemical methods are used to determine the corrosion rate of galvanic pairs of a high copper silver amalgam with Co-Cr dental alloys in artificial saliva. It is observed that when the difference in corrosion potentials of dissimilar alloys are small (less than 100 mVecs), Evans diagrams do not give good results, so the Mansfeld correction formulas must be used. Thus, it is found that the most resistant to corrosion is the pair formed between the amalgam and the bulk Co-Cr alloy (PG1,3) and that the corrosion products released in greater quantity to the electrolyte are those that contain ions of Co, Cr, Ag, Sr and Cu.

Parámetros bioquímicos y morfométricos vinculados a la dentición de búfalas. Relaciones con el número de incisivos

<p>La clasificación de las etapas productivas y la salud de un animal o del rodeo pueden establecerse por los cambios observables en los dientes incisivos y la determinación de los valores hematológicos. Este trabajo tuvo como objetivo evaluar el efecto de los cambios del número de incisivos permanentes sobre parámetros morfométricos y bioquímicos sanguíneos relacionados al metabolismo óseo en animales de 32 meses de edad. La investigación fue realizada en Corrientes, Argentina. Búfalas Murrah de 29 meses de edad (n=30), con dentadura decidua completa, fueron pesadas y mantenidas por 90 días en pasturas naturales. Al final del período se evaluó el número de incisivos permanentes erupcionados, la cantidad y nivel de erupción de piezas dentales, peso (PV), perímetro torácico (PT) y condición corporal (CC), tomándose muestras de sangre para determinar los valores de calcio, fósforo, magnesio y fosfatasa alcalina. La información obtenida fue analizada mediante estadística descriptiva, análisis de la varianza y correlación mediante el test de Pearson. El 37% mostró dos dientes, el 16% uno (derecho o izquierdo) y el 47% no presentó incisivos permanentes. Los valores de PV (kg) y PT (cm) para los individuos con incisivos deciduos, con uno o dos incisivos permanentes, fueron PV: 425,36 ± 16,13; 456 ± 17,67 y 426,64 ± 12,91 (p = 0,462) y PT: 190 ± 7,66; 197,20 ± 4,76; 189,91 ± 8,9 (p = 0,187) respectivamente, sin ser estadísticamente significativos. La magnesemia fue significativamente mayor en los animales sin incisivos y con un diente, comparados con aquellos con dos dientes erupcionados (r = -0,45; p < 0,05). Ninguna de las otras variables bioquímicas fueron influenciadas por la cantidad de piezas dentales (p ≥ 0,05). La condición corporal, así como las variables morfométricas y bioquímicas exploradas, no se vieron afectadas por las modificaciones de la cronometría dental, a excepción del magnesio sérico.</p>

Prevalencia de las extracciones prematuras en niños menores a 8 años.

Se considera pérdida prematura de un diente temporal cuando ocurre antes de su exfoliación natural siendo el único tratamiento viable la extracción de los dientes afectados, a pesar de los tratamientos preventivos odontológico, las extracciones dentales prematuras siguen siendo un procedimiento frecuente en la práctica odontológica. Objetivos: Determinar la prevalencia de las extracciones prematura en niños menores a 8 años, identificando causas y efectos que produces estos procedimientos quirúrgicos. Materiales y Métodos: Se realizó un estudio cuantitativo bibliográfico - documental, observacional, de campo, de corte transversal, tipo exploratoria, descriptiva. Que acudieron al subcentro esperanza del Carmen, de agosto del 2018 a marzo del 2019; se utilizó la técnica de observación y él instrumento que se aplico es la recolección de datos que se realizó mediante una tabla de observación, los resultados se les aplicó estadística descriptiva. Resultados: se estudiaron 43 pacientes, 26 fueron hombres, 17 mujeres, se extrajeron 67 órganos dentales debido a que algunos pacientes se les realizo 3 a 4 extracciones dentales, siendo la caries dental la enfermedad que más afecto a los pacientes con un promedio de 18 niños seguida de las enfermedades periodontales con 13 niños y las fracturas dentales provocadas por diferentes enfermedades que fueron 12 niños mientras la edad más susceptible fue el rango de 6 años con 16 niños atendidos. Conclusiones: Se determinó mediante el estudio realizado que los niños de 6 años presentan con mayor frecuencia perdidas de sus piezas dentales temporales y Se identificó las causas más comunes de la pérdida prematura de las piezas dentarias que fueron las caries dentales seguidas de las enfermedades periodontales que si no son tratadas inmediatamente con el profesional conlleva a la perdida de la pieza dental.

New insights on Hispanomys moralesi (Rodentia, Mammalia) and its use as biostratigraphical indicator

Here, we describe new specimens of the cricetid Hispanomys moralesi Lopez-Antonanzas et al. 2010, found in Batallones 4 site, which belongs to Cerro de los Batallones assemblage (Upper Vallesian, Upper Miocene). Previously, metrical and morphological data of H. moralesi have been used to proof whether the different sites within the butte were filled simultaneously or there was a time span among them (Lopez-Antonanzas et al. in Zool J Linnean Soc 160(4):725–747, 2010). 129 isolated molars, nine lower jaws, ten maxilla fragments and four skull remains from Batallones 4 were identified as H. moralesi and were included in the study. Length and width data were also taken on the dental pieces. This information has been used to perform a biometrical and morphological study, in order to compare the specimens of Batallones 4 with the rest of sites within the butte and with other Hispanomys species. The evolutionary stage of the fossils from Batallones 4 indicates that they are slightly more modern than the specimens from Batallones 10, and also have more primitive features than the ones from Batallones 1, 3 and 5. This information support the hypothesis by Lopez-Antonanzas et al. (2010): the cavities were not filled synchronously, but one after the other, beginning with southerner side of the butte (Batallones 10) and progressing towards north, being Batallones3 the last one to fill and, consequently, the youngest locality. The results remark the potential use of H. moralesi as a tool which can be used as a biochronological indicator that help us to relatively date a set of fossil sites.

Kinship analysis on skeletal ancient remains: The case of “el cerro de la horra” (Burgos, Spain)

The finding of a multiple simultaneous burial often suggests a close biological relationship among the individuals. In this context, this paper focuses on three very closely interred sub-adults in the site of El Cerro (La Horra, Burgos, Spain), a pit site of the Central Iberian Plateau dated to the Middle Bronze Age, ca. 1850-1450 cal BC.In this simultaneous triple burial two of the subadults were inhumed in lateral decubitus position intertwined face to face: a 7–8 years-old infant placed on his right side (HOR 02) and a second infant, perhaps male, about 11 years old, on the left (HOR 03), keeping a purposefully symmetrical disposition. On top of these corpses, and occupying the space between them, was placed a third subadult (HOR 01), a juvenile of 11–15 years, probably female.We have selected different teeth samples from each one of these individuals for genetic analysis, with the aim of enlightening their alleged kinship relationship, which could be key in the interpretation of the site and the overall cultural practices.To perform the kinship analysis, we have extracted and amplified DNA from three dental pieces from individuals HOR01 and HOR02, and two from HOR03. The DNA markers analysed were autosomal short tandem repeats (STRs), autosomal insertion – deletion markers (InDels) and HVI and HVII regions of mitochondrial DNA (mtDNA). Nevertheless, the poor preservation state of the DNA did not allow the obtention of reliable results autosomal markers. However, the mitochondrial DNA analysis provide the same haplotype to the three individuals (16298C 64T 72C, in the range: (16105–16399) (57–128)), belonging to HV0 mitochondrial haplogroup. The results point to a kinship among all the individuals through the maternal lineage.

Subtractive vs additive manufacturing in the production of zirconia pieces for dental applications

Introduction: Ceramic based prosthetic materials for dental restorations have been playing an important role in the dentistry industry, due to their mechanic and aesthetic properties, chemical stability and biocompatibility. Additive manufacturing (AM) is an emerging alternative to the conventional subtractive techniques (SM), to obtain dental pieces, since it is able to produce customized complex 3D pieces at low cost, decreasing the material’ waste and the production time. In particular, robocasting (RC), which is an extrusion filament-based 3D printing process, seems promising for this purpose. However, concerns regarding the material’s intrinsic final properties may arise. The aim of this study is to evaluate the potential of the robocasting technique to produce reliable zirconia dental structures, comparing several properties of the samples produced. Materials and methods: Yttria stabilized-Zirconia (5 wt% Y2O3) pieces were produced by subtractive manufacturing (SM) and robocasting (AM). Samples were sintered at 1500 °C and polished. Density and porosity were determined by the Archimedes method and by optical microscopy, respectively. The topography/morphology was analysed by atomic force microscopy. Wettability measurements with water were performed by the sessile drop method. Vickers hardness was also determined with an applied load of 98 N. In average, 10 measurements were done for each technique. Results: The obtained results are summarized in Table 1. AFM images are shown in Figure 1. Figure 1. AFM topographical images of SM and AM samples Discussion and conclusions: Contrarily to SM samples that present a density very similar to the theoretical value, AM samples present a lower value (95.5%). This explains the higher porosity observed for AM samples. Although the surface roughness of the samples is similar, different values were found for wettability. Nevertheless, both are hydrophilic. Finally, AM samples hardness is significantly lower than that found for SM samples. In conclusion, there are still some challenges to overcome to produce AM samples for dental applications, in particular relatively to material’s densification. The samples’ porosity may compromise the materials’ mechanical properties, like toughness.

Influence of relative humidity and low temperature hydrothermal degradation on fretting wear of Y-TZP dental ceramics

Dental pieces are subjected to constant friction due to grinding during mastication and mouth disorders such as bruxism. Therefore, wear resistance of Y-TZP materials used for dental prostheses must be investigated. In this work, the influence of humidity and low temperature hydrothermal degradation (LTD) in 3Y-TZP ceramics subjected to fretting has been evaluated. A 100% r.h. reduces the effects of wear due to the lubricative effect of water, compared to those at ambient r.h. COF, wear volume and damage are considerably lowered at a r.h. of 100%. Exposure to degradation conditions for 25 h increased the vulnerability to wear damage of LAVA grade Y-TZP sintered at 1400 °C since the critical grain size of 300 nm was exceeded.

Effectiveness of eighth generation adhesives in direct restoration after dental clearance

At the present time, aesthetics in dentistry have been in great demand, so dental clarifications are a highly sought after treatment by patients, for which they go to the dental office daily, they have produced a great controversy in dental restoration treatments due to the materials that compose it. One of its main failures is the difficulty of the level of adhesion that affects both enamel and dentin. Through a quantitative methodology it was analyzed by means of the scanning electron microscope in 40 dental pieces (premolars) extracted by orthodontic treatment, they were divided into 4 groups of 10 samples each- This in vitro research will allow to observe, the degree of adhesion of a Direct restoration after dental clearance according to the time in which it is performed and prior to prophylaxis with sodium bicarbonate and an antioxidant such as calcium hydroxide using the same last generation adhesion system (ULTRADENT PEAK-Universal). This investigation led to a statistical and observational result that the sodium bicarbonate group showed a higher level of adhesion compared to the other groups approaching with a minimum of difference the control group which was the benchmark for comparison. It was concluded that performing a sodium bicarbonate prophylaxis helps the level of adhesion post clearance.

A Dual-Platform Laser Scanner for 3D Reconstruction of Dental Pieces

Abstract This paper presents a dual-platform scanner for dental reconstruction based on a three-dimensional (3D) laser-scanning method. The scanner combines translation and rotation platforms to perform a holistic scanning. A hybrid calibration method for laser scanning is proposed to improve convenience and precision. This method includes an integrative method for data collection and a hybrid algorithm for data processing. The integrative method conveniently collects a substantial number of calibrating points with a stepped gauge and a pattern for both the translation and rotation scans. The hybrid algorithm, which consists of a basic model and a compensation network, achieves strong stability with a small degree of errors. The experiments verified the hybrid calibration method and the scanner application for the measurement of dental pieces. Two typical dental pieces were measured, and the experimental results demonstrated the validity of the measurement that was performed using the dual-platform scanner. This method is effective for the 3D reconstruction of dental pieces, as well as that of objects with irregular shapes in engineering fields.

Impact of social determinants on tooth loss. Bibliographic review

In Chile, dental caries is one of the most prevalent chronic oral diseases along with gingival, periodontal diseases and dentomaxillary anomalies. Chronic diseases represent the bulk of Chile’s health burden. These diseases are associated with habits that are usually acquired early in childhood or adolescence and that are also associated with a complex and multiple network of determinants. The social determinants of health are defined as the social conditions in which people live and they work, and they influence positively or negatively on health. Social determinants intervene markedly in oral health, where people with fewer resources and lower educational level have more pathologies and less access to treatments. The empirical evidence analyzed provides useful information to consider that the Social Determinants of Health have a great influence on the health of the individuals, however, there are few investigations that directly relate the loss of dental pieces with these determinants. The objective of this article is to review the association between tooth loss and the social determinants of health.

Clinical management of the vertical dimension with fixed prosthesis and removable partial denture, with rotational insertion axis

The alteration of the vertical dimension can be caused by different factors, among which, we find partial loss of dental pieces, pathological wear of the occlusal surfaces that are caused by different etiologies, being one of the most common bruxism. This results in alterations in the stomatognathic system that causes aesthetic and functional sequelae. That is why the importance of theoretical and clinical knowledge of partial edentulism when the vertical dimension is altered, because as we know there are currently many biomaterials and techniques to rehabilitate a patient with these characteristics, however, all part of a correct diagnosis. Traditionally different methods have been used to establish the appropriate vertical dimension; however, there is not yet a single method capable of providing total accuracy. The objective of this work is to share the approach to a patient with alteration of the vertical dimension through the manufacture of fixed prosthesis and PPR with double insertion axis. Main data a complete 82-yearold edentulous patient who had a decrease in the vertical dimension due to parafunctional habit (centric and eccentric bruxism) was completely rehabilitated. Main comments: The results were satisfactory for the patient since full rehabilitation was achieved through combined prosthesis (fixed and removable) thus restoring the vertical dimension and therefore having functional and aesthetic results. Conclusions: The use of fixed prosthesis and PPR double axis of insertion is an alternative of treatment that allows returning of optimal form the functions of the oral cavity giving like result the comfort of the patient.