PurposeThe aim of this study was to analyze the anatomical dimensions of the buccal bone walls of the aesthetic maxillary region for immediate implant placement, based upon cone-beam computed tomography (CBCT) scans in a sample of adult patients.MethodsTwo calibrated examiners analyzed a sample of 50 CBCT scans, performing morphometric analyses of both incisors and canines on the left and right sides. Subsequently, in the sagittal view, a line was traced through the major axis of the selected tooth. Then, a second line (E) was traced from the buccal to the palatal wall at the level of the observed bone ridges. The heights of the buccal and palatal bone ridges were determined at the major axis of the tooth. The buccal bone thickness was measured across five lines. The first was at the level of line E. The second was at the most apical point of the tooth, and the other three lines were equidistant between the apical and the cervical lines, and parallel to them. Statistical analysis was performed with a significance level of P≤0.05 for the bone thickness means and standard deviations per tooth and patient for the five lines at varying depths.ResultsThe means of the buccal wall thicknesses in the central incisors, lateral incisors and canines were 1.14±0.65 mm, 0.95±0.67 mm and 1.15±0.68 mm, respectively. Additionally, only on the left side were significant differences in some measurements of buccal bone thickness observed according to age and gender. However, age and gender did not show significant differences in heights between the palatal and buccal plates. In a few cases, the buccal wall had a greater height than the palatal wall.ConclusionsLess than 10% of sites showed more than a 2-mm thickness of the buccal bone wall, with the exception of the central incisor region, wherein 14.4% of cases were ≥2 mm.

The aim of this study was to analyze the influence of three different transmucosal heights of the abutments in single and multiple implant-supported prostheses through the finite element method. External hexagon implants, MicroUnit, and EsthetiCone abutments were scanned and placed in an edentulous maxillary model obtained from a tomography database. The simulations were divided into two groups: (1) one implant with 3.75 × 10 mm placed in the upper central incisor, simulating a single implant-supported fixed prosthesis with an EsthetiCone abutment; and (2) two implants with 3.75 × 10 mm placed in the upper lateral incisors with MicroUnit abutments, simulating a multiple implant-supported prosthesis. Subsequently, each group was subdivided into three models according to the transmucosal height (1, 2, and 3 mm). A static oblique load at an angle of 45 degrees to the long axis of the implant in palatal-buccal direction of 150 and 75 N was applied for multiple and single implant-supported prosthesis, respectively. The implants and abutments were assessed according to the equivalent Von Mises stress analyses while the bone and ceramics were analyzed through maximum and minimum principal stresses. The total deformation values increased in all models, while the transmucosal height was augmented. The transmucosal height of the abutments influences the stress values at the bone, ceramics, implants, and abutments of both the single and multiple implant-supported prostheses, with the transmucosal height of 1 mm showing the lowest stress values.

CURIQUEO, A.; SALAMANCA, C.; BORIE, E.; NAVARRO, P. & FUENTES, R. Evaluación de la fuerza masticatoria máxi-ma funcional en adultos jóvenes chilenos. Int. J. Odontostomat., 9(3):443-447, 2015.RESUMEN: La fuerza masticatoria máxima funcional (FMMF) se ha definido como la máxima fuerza generada entre los dientes maxilares y mandibulares. Así el objetivo de esta investigación fue de obtener datos reales sobre las FMMF a nivel molar, premolar, canino e incisivo en individuos adultos jóvenes. El estudio incluyó una muestra de 50 individuos entre 18 y 25 años de edad, totalmente dentados y con perfil esqueletal tipo I y clase I molar y canino. Se utilizó como instrumento un dispositivo de medición de fuerzas portátil, realizando las medidas en la región molar, premolar, canina e incisiva. A los individuos se les indicó morder el instrumento con la mayor fuerza posible, alternando las diferentes zonas a medir, aplicándo-se tres mediciones en cada diente y registrando el mayor valor en cada zona. La media de las fuerzas ejercidas del sexo masculino fue de 698, 516, 322 y 220 N, en las regiones molar, premolar, canina e incisiva, respectivamente. Por otro lado, en el sexo femenino se observaron valores medios de 466, 431, 232 y 174 N en las regiones molar, premolar, canina e incisiva, respectivamente. Se puede concluir que se observaron diferencias significativas de FMMF entre ambos sexos en las diferentes regiones, identificando los mayores valores en los individuos de sexo masculino en la región molar. Además, se identificaron diferencias significativas de la FMMF sólo en la región canina del sexo masculino al relacionarlas con el lado del arco.PALABRAS CLAVE: fuerza máxima de mordida, adultos jóvenes, mordida. INTRODUCCIÓNLa fuerza masticatoria máxima funcional (FMMF) ha sido definida como la máxima fuerza que se genera entre los dientes maxilares y mandibulares (Fontijn-Tekamp et al., 2000). Ésta es asociada directamente con la salud del sistema masticatorio (Kampe et al., 1987;Ow et al., 1989), teniendo influencia en el desarrollo de las estructuras anexas a la boca, tales como músculos y los dientes (Braun et al., 1995;. Por lo tanto, la FMMF puede servir como un método de diagnóstico y evaluación, permitiendo entregar información útil y objetiva de la oclusión del individuo (Shinogaya et al., 1999).Existen diferentes factores que pueden influir en la FMMF, tales como las condiciones de la dentición, fuerza de los músculos de la masticación, condiciones de la articulación témporo mandibular (ATM) y umbral del dolor del sujeto, entre otros factores (Tortopidis et al., 1998;Antonarakis et al., 2013). Abu Alhaija et al. (2010) asocian a los sujetos de una morfología facial braquicéfala con una mayor fuerza de masticación en comparación con los meso o dolicocéfalos.La FMMF también está asociada al tipo de alimentación. Así, se ha observado una mayor FMMF en sujetos con una dieta rica en alimentos de mayor dureza y fibras (Yamanaka et al., 2009;Borie et al., 2014). Además, la fuerza masticatorias decrece a medida que au...

We present the case of a 13-year-old patient with bilateral transmigration of mandibular canine associated with multiple composite odontoma. Impacted canines are very uncommon, with a 0.1 % to 3.6 % prevalence of appearance. The presence in the mandible is less frequent. The odontoma development is often associated with the impacted canines. The etiology is unknown but is associated with traumatic, infectious, hereditary or genetic factors. This pathology is asymptomatic and associated with eruption disorders in temporal and permanent dentition.

SUMMARY:The temporomandibular joint (TMJ) is composed of bony structures, cartilage, capsule, articular disc, synovial membrane and ligaments. Some authors consider the "Tanaka ligament" described in the 1980s by Terry Tanaka as an intra-capsular ligament of the TMJ that unites medially the articular disc and mandibular fossa. The aim of the present study was to analyze the use of the term "Tanaka ligament" in the literature evaluating the scientific support of its existence. A literature review was carried out under the terms "Tanaka Ligament [AND] TMJ" and "Ligamento Tanaka [AND] ATM" (Spanish and Portuguese) in the search engines: MEDLINEPubmed, Science Direct, Google Scholar, LILACS-Bireme and SciELO. Scientific articles and theses were considered in English, Spanish and Portuguese. A total of 1,355 studies were found, summing up the results of all the search engines, of which 8 studies (5 articles and 3 theses) were selected after applying inclusion and exclusion criteria, selection by title, abstract and content. Most of these studies were discarded because they had contents related to the TMJ and/or ligaments wherein an author used the surname "Tanaka", that were not related to the Tanaka ligament. Among the 8 selected studies, 6 of them cite text books, 1 cites a video published by Terry Tanaka and 1 cites a thesis. Most of these textbooks cited also refer to videos by Terry Tanaka and his books. Moreover, most of the anatomical literature does not consider this ligament as an individualized structure. Although there are descriptions of Tanaka's ligament in textbooks, the scientific support of its existence is based only on videos and texts by Terry Tanaka. The dissemination of knowledge associated with this ligament must be cautious, as there is a need for further morphological and functional studies to confirm its existence.

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Aim: To evaluate the risk of nonsyndromic orofacial clefts (NSOFCs) associated with LINE-1 methylation, as a marker of global DNA methylation, and the effect of MTHFR functional variants on this variable. Patients & methods: LINE-1 methylation was evaluated by bisulfite modification coupled to DNA pyrosequencing in 95 NSOFC cases and 95 controls. In these subjects, MTHFR genotypes for variants c.C677T (rs1801133) and c.A1298C (rs1801131) were obtained. Results: Middle levels (second tertile) of LINE-1 methylation increase the risk of NSOFCs. In addition, LINE-1 methylation depends on c.A1298C genotypes in controls but not in cases. Conclusion: A nonlinear association between global DNA methylation and NSOFCs was detected in this Chilean population, which appears to be influenced by MTHFR functional variants.

ObjectiveTo assess the association between polymorphic variants from SHMT1 and MTHFS genes, involved in the cytoplasmic futile folate cycle, and the risk of nonsyndromic cleft lip with or without cleft palate (NSCL/P) in the Chilean population.Subjects and MethodsIn a sample of 139 Chilean NSCL/P cases and 278 controls, we obtained the genotypes for nine variants of SHMT1 and MTHFS and the association between them and the phenotype was evaluated using odds ratios (OR) in additive (allele), dominant, and recessive models.ResultsAfter correction for multiple comparisons, only the variant rs1979277 (G > A; p.Leu474Phe) from SHMT1 showed a significant and protective effect for additive (OR 0.60; 95% CI 0.42–0.86; p = .0054, q = 0.0488) and dominant models (OR 0.48; 95% CI 0.29–0.75; p = .0009; q = 0.0081). Our bioinformatic prediction plus functional evidence from previous reports demonstrate that the A allele for this missense variant decreases the enzymatic activity.ConclusionsOwing to the rs1979277 A allele, which reduces the cytoplasmic SHMT activity and has a higher frequency in controls than in NSCL/P cases, we hypothesized that a low enzyme activity may increase the cytoplasmic concentration of folates and, therefore, explain the protective role against OFCs.