Dexamethasone inhibits BMP7-induced osteogenic differentiation in rat dental follicle cells via the PI3K/AKT/GSK-3ß/ß-catenin pathway.

Impacted third molars are commonly seen in teenagers and young adults and can cause considerable suffering. Preventing eruption of the third molars can reduce pain at the source. Our previous study has shown that dexamethasone (DEX) at a certain concentration can prevent the eruption of third molars without damaging alveolar bone in Sprague-Dawley (SD) rats, but the relevant molecular mechanisms need to be explored. This study aimed to explore the effects of high concentrations of DEX on osteogenic signaling pathways, including BMP/Smad and Wnt/ß-catenin pathways, in rat dental follicle cells (rDFCs) and to elucidate the possible mechanisms. The results showed that BMP7 induced osteogenic differentiation by increasing the activity of ALP and the protein levels of OPN in rDFCs. DEX decreased endogenous BMP7 and phosphorylated Smad1/5/8 expression as well as BMP7-induced osteogenic differentiation. DEX also reduced the mRNA and protein levels of ß-catenin by enhancing the expression of GSK-3ß. In addition, regardless of DEX intervention, overexpression of BMP7 promoted the expression of ß-catenin, while knockdown of BMP7 attenuated it. Further investigation revealed that overexpression of BMP7 attenuated the DEX-mediated inhibition of AKT and GSK-3ß phosphorylation, but knockdown of BMP7 exerted the opposite effects. This study suggests that high concentrations of DEX may inhibit the expression of ß-catenin via the PI3K/AKT/GSK-3ß pathway in a manner mediated by BMP7. The findings further illustrate the possible molecular mechanisms by which DEX prevents tooth development.

Morfología radicular de los terceros molares / Root canal morphology of third molars

Introducción: la morfología radicular es una característica del tercermolar que puede incrementar el grado de difi cultad de la odontectomía,lo que hace necesario indagar sobre sus aspectos anatómicos más frecuentes. Objetivo: Conocer la morfología radicular de los terceros molares. Material y métodos: Se valoraron 155 tomografías computarizadas cone-beam (TCCB) de pacientes ≥ 16 años de edad, de ambos sexos, con al menos un tercer molar retenido o erupcionado con desarrollo radicular completo. Las características estudiadas fueron el número, longitud, diámetro y forma de las raíces. Resultados: Los terceros molares superiores presentaron con mayor frecuencia raíces fusionadas (57.9 por ciento) en forma cónica sobre su eje (27.2 por ciento). Los casos con raíces separadas mostraron más comúnmente una curvatura hacia distal en el tercio medio de la raíz vestíbulo-mesial (35 por ciento), mientras que la forma predominante de la raíz vestíbulo-distal fue la recta sobre su eje longitudinal (28.8 por ciento). Las formas más frecuentes de la raíz palatina fueron la recta sobre su eje longitudinal y la recta palatinizada conigual número de casos (18.7 por ciento), siendo ésta la que tuvo mayor longitud (11.7 ± 1.7 mm) y diámetro en sus diferentes tercios (cervical 4.8 ± 0.9 mm, medio 4 ± 1.1 mm y apical 2.8 ± 0.9 mm). Los terceros molaresinferiores presentaron mayormente dos raíces (75.9 por ciento) convergentes yseparadas por un septum óseo (38.1 por ciento), siendo la raíz vestíbulo-distal la que presentó mayor diámetro en sus diferentes tercios (4.1 ± 1 mm,3.4 ± 0.7 mm y 2.3 ± 0.6 mm, respectivamente). Conclusiones:Las características de las raíces de los terceros molares observadas en la TCCB se acercan a las descripciones anatómicas. Se observaron, además, múltiples variaciones en su forma, tanto en las fusionadas como en las separadas. Este aspecto morfológico debe ser tomado en cuenta para prever el grado de dificultad de la odontectomía del tercer molar.

Introduction: The root morphology of third molars is something thatcan make extraction more diffi cult, which is why research is needed intothe most common anatomical aspects of this characteristic. Objective:To understand the root morphology of the third molar. Material andmethod: 155 cone-beam computed tomography (CBCT) images ofpatients aged ≥ 16 years of both sexes with at least one retained orerupted third molar with complete root development were examined.The features assessed were: number, length, diameter, and shape ofthe roots. Results: The upper third molar was found to have a greaterfrequency of fused (57.9%) and cone-shaped roots (27.2%). Cases ofseparate roots most commonly displayed distal curvature towards themiddle third of the mesiobuccal root (35%), while the distobuccal rootwas more typically straight along its longitudinal axis (28.8%). Thepalatal root was most commonly either straight along its longitudinalaxis or its palatal side (18.7% in both cases), the latter being longer(11.7 ± 1.7 mm) and having a greater diameter in each of its threesections (cervical 4.8 ± 0.9 mm, middle 4 ± 1.1 mm, and apical 2.8 ±0.9 mm). The presence of two converging roots (75.9%) and two rootsseparated by an interdental septum (38.1%) was more common in lowerthird molars, with the distobuccal root having the greatest diameterin each of its three sections (cervical, 4.1 ± 1 mm, middle, 3.4 ± 0.7mm, and apical 2.3 ± 0.6 mm). Fused roots were longer (11.6 ± 1.8mm) and most commonly cone-shaped with distal tapering (27.7%).Conclusions: The characteristics observed in the CBCT images of theroots of the third molars were similar to those described in anatomicalliterature. Furthermore, multiple variations were found in their shape, inboth the fused and the separate root canals. This morphological aspectshould be taken into consideration in order to determine the degree ofdiffi culty of a third molar extraction.

Does Orthodontic Extraction Treatment Improve the Angular Position of Third Molars? A Systematic Review.

PURPOSE: To systematically assess the available evidence on the effect of orthodontic extractions on third molar (M3) angulation. MATERIALS AND METHODS: Three databases were searched up to April 25, 2016 to identify orthodontic studies comparing M3 angular changes in patients with and without extraction. Information on methodology, treatment procedures, and outcome was retrieved from each study. Assessment of overall and individual quality of the included studies was performed using validated criteria. RESULTS: Fourteen retrospective studies were considered eligible for this systematic review. Two studies achieved a moderate evidence score, whereas the lowest grade was assigned to 12 studies. The overall evidence level was classified as limited. Meta-analysis was not feasible because of the high heterogeneity across studies. Based on the best available evidence, premolar extraction followed by fixed orthodontic appliances can substantially improve the angular position of M3s by 10° to 18°. CONCLUSIONS: There is limited evidence that orthodontic extractions can substantially enhance the uprighting of M3s. Clinicians should be aware of the potentially beneficial effect of orthodontic extraction treatment on M3 development, although well-designed prospective studies are necessary to strengthen this statement.

Impacted Teeth: An Interdisciplinary Perspective.

A tooth normally erupts when half to three-quarters of its final root length has developed. Tooth impaction is usually diagnosed well after this period and is generally asymptomatic. It is principally for this reason that patients seek treatment later than optimal. Tooth impaction is a common problem in daily orthodontic practice and, in most cases, it is recognized by chance in a routine dental examination. Therefore, it is very important that dental practitioners are aware of this condition, since early detection and intervention may help to prevent many harmful complications. The treatment of impacted teeth requires multidisciplinary cooperation between orthodontists, oral surgeons and sometimes periodontists. Orthodontic treatment and surgical exposure of impacted teeth are performed in order to bring the impacted tooth into the line of the arch. The treatment is long, more complicated and challenging. This article presents an overview of the prevalence, etiology, diagnosis, treatment and complications associated with the management of impacted teeth.

Retenção prolongada de dente decíduo por impactação de dente supranumerário em criança de 12 anos / Tooth prolonged retention of deciduous tooth impaction supernumerary in children under 12 years

Dente supranumerário é definido como um distúrbio de desenvolvimento caracterizado pela presença de um ou mais elementos dentários fora do número considerado normal de uma arcada. A ocorrência dos supranumerários pode ocasionar uma variedade de complicações, como por exemplo, apinhamento de dentes permanentes, erupção retardada e/ou ectópica, rotação dentária, formação de diastema, desenvolvimento de lesões císticas, reabsorção de dentes adjacentes. Na maioria das vezes o diagnóstico da presença desse elemento é realizado por exame clínico e radiográfico de rotina. O objetivo do presente trabalho foi relatar um caso clínico de retenção prolongada de um dente decíduo e erupção retardada de um dente permanente em decorrência da presença de um elemento supranumerário diagnosticado apenas aos 12 anos de idade. Após a identificação do elemento supranumerário e análise de exames radiográficos complementares,foi realizada cirurgia para remoção dos elementos decíduo e supranumerário, bem como acompanhamento por três meses do processo eruptivo do elemento impactado,um segundo pré-molar inferior direito o qual se posicionou favoravelmente na arcada dentária. Concluiu-se que a detecção em momento oportuno e a remoção de elementos supranumerários, também respeitadas à necessidade e oportunidade cirúrgica, são importantes para evitar danos futuros à oclusão dos pacientes, devendo-se dar importância ao acompanhamento e evolução clínica do caso.

Supernumerary teeth is defined as a developmental disorder characterized by the presence of one or more dental elements out of a number considered normal arch. The occurrence of supernumerary can cause a variety of complications, such as crowding of the permanent teeth,delayed and / or ectopically erupting, tooth rotation, diastema training, development of cysticlesions, resorption of adjacent teeth. In most cases the diagnosis of the presence of this elementis made by clinical examination and routine radiographic. The aim of this study was to reporta case of prolonged retention of a primary tooth eruption and delayed a permanent tooth dueto the presence of a supernumerary element diagnosed only 12 years old. After identifying the supernumerary element and analysis of complementary radiographs, it was carried out surgeryto remove the elements deciduous and supernumerary and monitoring for 3 months of the eruptive process impacted element, a premolar law that favorably-positioned in the dental arch.It was concluded that the timely detection and removal of supernumerary elements also respected the need and surgical opportunity, are important to prevent future damage to the occlusion of patients, should be given importance to the monitoring and clinical outcome.

Perioperative bromelain reduces pain and swelling and improves quality of life measures after mandibular third molar surgery: a randomized, double-blind, placebo-controlled clinical trial.

PURPOSE: The purpose of the present study was to compare the effect of oral bromelain (4 × 250 mg) versus oral diclofenac sodium (4 × 25 mg) on pain, swelling, trismus, and quality of life (QOL) after surgical removal of impacted lower third molars. PATIENTS AND METHODS: A randomized, double-blind, placebo-controlled study was planned. The sample included patients requiring extraction under local anesthesia of a single partial bony impacted mandibular third molar. The patients were randomly distributed into 1 of 3 groups: bromelain, diclofenac, and placebo. Treatment started 1 day before surgery and continued for 4 days. The predictor variable was the type of the drug given to the patients. The outcome variables were pain, swelling, and trismus, which were measured at 1, 3, and 7 days postoperatively. The other study variables included QOL measures to assess the patients' perception regarding the effect of surgery on their well-being and daily activities. A validated questionnaire was used to measure QOL. The data were analyzed using analysis of variance, multiple measures analysis of variance, or Pearson's χ(2) test, as appropriate. P < .05 was considered significant. RESULTS: A total of 45 subjects requiring surgical removal of a single impacted mandibular third molar under local anesthesia were included in the present study. The bromelain and diclofenac groups both showed a significant reduction in pain compared with the placebo group at all intervals (P < .05). Diclofenac also resulted in a significant reduction of swelling at 3 and 7 days, and bromelain resulted in an insignificant reduction. A nonsignificant reduction in trismus occurred in both treatment groups compared with the placebo group. Both treatment groups also showed a significant difference in the effect on QOL in most subscales and total scores (P < .05). The effect was comparable between the 2 treatment groups for all parameters and at all intervals. CONCLUSIONS: The results of our study have shown that oral bromelain is an effective therapy to improve the QOL after surgical removal of impacted lower third molars, with an effect on the postoperative sequelae comparable to that of preemptive diclofenac sodium.

Prophylaxis of impacted teeth using MRI and focal ultra-sound ablation? a feasible hypothesis.

UNLABELLED: Teeth start as bi-layered epithelial soft tissue follicles within bony jaws. Follicles grow into teeth and erupt. Early third molar follicles are detectable 8-9 years (±9 months). Intra-oral dental arches of jaws have finite space accommodating formed crowns. The last teeth to erupt are third molars. When the space needed by all the teeth exceeds the total arch space available, wisdom teeth may become impacted in bone. Lower impactions are more prevalent due to the mandible shape, and impaction associated pathologies with erupting partially or totally impacted teeth are common. Impacted third molars are universally prevalent from 17 to 23 years. Third molar impactions are sources of infection, pain, cyst formation and contribute to malocclusions and other pathologies. Surgical removal of third molars is traumatic, invasive and painful and may produce complicating morbidities. Magnetic resonance imaging (MRI) is used to locate lesions with clear definition and accurate targeting, both in soft and hard tissue organs. Focused ultrasound (FUS) is used to ablate hard and soft tissue structures and stops growth of targeted pathologies. For example, FUS is used to ablate CNS brain tumours, cell causing Parkinson's disease, prostatic growths and thrombolysis in strokes. HYPOTHESIS: Modern imaging techniques, like MRI, can accurately locate third molar follicles at age 9, before wisdom teeth form and grow. MRI in combination with FUS could be used to ablate follicles of third molars, stop tooth growth (both crown and root) and so avoid later impactions.

Prevenção da impacção de caninos permanentes inferiores: relato de caso / Prevention of permanent mandibular canine impactation: case report

O presente trabalho aborda um tema pouco explorado na literatura, a impactação de caninos inferiores permanentes, ilustrando o acompanhamento longitudinal de um caso clínico. O tratamento de canino inferior impactado é bastante complexo, envolvendo diferentes condutas, inclusive a sua extração. Logo, a prevenção de tal possibilidade constitui-se de extrema importância. Como meios preventivos, têm-se o diagnóstico e a intervenção precoce. O diagnóstico precoce permite a opção pela conduta terapêutica interceptadora, prevenindo a impactação do canino permanente e suas consequências. A intervenção precoce pode economizar do paciente tempo, custos, tratamentos mais complexos e injúrias a qualquer outro dente saudável.

Effects of first molar extraction on third molar angulation and eruption space.

OBJECTIVES: The aim was to investigate the effects of orthodontic treatment with 4 first molar extractions on the angulations and eruption spaces of all third molars and to compare these changes with outcomes of nonextraction samples used as a control group. STUDY DESIGN: This study was carried out on standardized panoramic radiographs of 41 subjects (8 male, 33 female) with a mean age of 16.6 years (range 13 to 20 years). Twenty-one of the subjects were orthodontically treated with extraction of the 4 first permanent molars, and 20 had nonextraction treatment. The angulational changes and eruption spaces of third molars were evaluated on the panoramic radiographs taken before treatment and at the end of the observation period. RESULTS: Analysis of the linear variables demonstrated a statistically significant difference between the 2 groups for all third molar eruption spaces (P < .001). The mean differences in the third molar eruption spaces between the pretreatment and posttreatment values for the first molar extraction group were higher than those of the nonextraction cases. CONCLUSION: Orthodontic treatment accomplished with extractions of the permanent first molars increases the eruption spaces of third molars and decreases their impaction. In addition, it has greater favorable effect on the angulation of the upper third molars than of the lower third molars.

Maxillary canine impactions: orthodontic and surgical management.

With the exception of the maxillary and mandibular third molars, the maxillary canine is the most commonly encountered impaction. In North America, palatally located impactions appear to predominate over labially impacted canines and occur more frequently in women. Because of the common nature of this phenomenon, the general dentist should know how to properly diagnose and manage potential disturbances in the eruption of the maxillary canine. If diagnosed early, and when clinically and radiographically indicated, extraction of the deciduous canine may help correct the eruption path of the permanent tooth and prevent impaction. This article reviews the etiology, prevention, and surgical and orthodontic management of impacted cuspids. Because the general dentist is often the first dental care provider to come in contact with patients with impacted canines, knowledge about this common dental anomaly is essential to provide proper comprehensive therapy.

El tercer molar mandibular, método predictivo de erupción / The mandibular third molar, an eruption predictive method

Una de las inquietudes de los odontólogos, principalmente de los especialistas en ortodoncia y cirugía bucal, es saber cuándo se hace necesario extraer los terceros molares o cuándo dejarlos para que completen con éxito su erupción. En este trabajo se pretende establecer un método predictivo sobre radiografías panorámicas que nos permita tomar la decisión acertada.

Impacted teeth: prophylactic extractions or not?

Pathologic changes related to impacted teeth are infrequent. However, considerable damage to bone and adjacent teeth may result if they do occur. Four patients are described in whom different circumstances existed with impacted teeth. Extractions are indicated when the anatomic location of the impacted teeth is most favorable and when the patient's systemic and hematologic condition is least compromising, even if the teeth are asymptomatic at that time.

Patients' retrospective preference for extraction of asymptomatic third molars.

The purpose of this study was to determine the personal utility of asymptomatic third molar removal in military patients. From 1 to 30 days (mean = 7.4) after the extraction of one or more third molars, 100 returning patients (all male, mean age = 20.1) were asked to respond to hypothetical questions concerning the extraction of asymptomatic third molars. If the likelihood of third molars ever having to be removed was given as 10%, 50%, and 100%, then 45%, 61%, and 88% of responses, respectively, showed preference for immediate extraction. When respondents chose to delay treatment until there was a problem, no likelihood group would tolerate more than 2.77 additional days of post-extraction pain before changing their preference to immediate extraction. 87% of respondents preferred extractions prior to a deployment which would make treatment delivery difficult, and 89% prior to becoming a civilian at which time treatment might no longer be free. The results indicate general acceptance of the strategy of prophylactic third molar removal among a sample of military patients who have undergone pre-treatment counseling and the surgical procedure. A question remains as to the personal utility that might be measured prior to surgery.