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.

The effect of first and second premolar extractions on third molars: A retrospective longitudinal study.

OBJECTIVES: To analyse the effect of first and second premolar extractions on eruption space for upper and lower third molars and on third molar position and angulation during orthodontic treatment. METHODS: The sample consisted of 296 patients of which 218 patients were orthodontically treated without extraction and 78 patients with extraction of first or second premolars. The eruption space for third molars was measured on pre- and posttreatment lateral cephalograms, whereas the angulation, vertical position, the relation with the mandibular canal and the mineralization status of third molars were evaluated using pre- and posttreatment panoramic radiographs. All data were statistically analyzed. RESULTS: The increase in eruption space and the change in vertical position of upper and lower third molars significantly differed between patients treated with and without premolar extractions, whereas the change in angulation, relationship with the mandibular canal and mineralization status of the third molars did not significantly differ between patients treated with and without premolar extractions. CONCLUSIONS: The retromolar space and the position of third molars significantly change during orthodontic treatment in growing patients. Premolar extractions have a positive influence on the eruption space and vertical position of third molars, whereas they do not influence the angular changes of third molars. Due to the retrospective character of the study, these conclusions should be carefully considered. Further prospective research is necessary for better insights into this complex topic. CLINICAL SIGNIFICANCE: This study stresses the importance of considering the possible effects of orthodontic treatment on third molars during treatment planning.

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.

Etiology, Classification and Management of Ectopic Eruption of Permanent First Molars.

Ectopic eruption of a permanent tooth involves abnormal resorption of a portion or all of the adjacent primary tooth. Among the most commonly ectopically erupted teeth are the permanent first molars. Ectopically erupting molars may require intervention to allow for full eruption, or they may spontaneously self-correct and erupt into occlusion. Decisions regarding the necessity of intervention, its ideal timing, and intervention type are multifactorial. Treatment options for the ectopically erupting permanent first molar include the elastomeric separator, brass wire, pre-fabricated clip separator, custom made appliances (Humphrey appliance, Halterman appliance), or extraction of the primary molar. Early intervention when indicated can ensure proper full eruption of the permanent first molar and prevent mesial angulation, arch perimeter loss, tooth impaction and ankylosis. Two cases are described that manage ectopic eruption of the permanent first molar.

Permanent maxillary canines - review of eruption pattern and local etiological factors leading to impaction.

The position of the permanent maxillary canine at the angle of the mouth is strategically significant in maintaining the harmony and symmetry of the occlusal relationship. However, the maxillary canine is the second most frequently impacted tooth, with prevalence reported to be between 1% and 2%. Moreover, treatment of this condition is often complex and involves substantial time and financial cost. Hence, it is only prudent to monitor the eruption and identify the etiological factors that lead to impaction of the maxillary canine. Numerous researchers have tried to identify specific and nonspecific etiological factors responsible for displacement of canines. The purpose of this review was to track the development processes of maxillary canines and determine the hindrances that affect the eruption at different ages. Awareness of the eruption process and etiology of noneruption will help to reduce the incidence of impacted canines by allowing for early recognition and interceptive treatment.

Impacted wisdom teeth.

INTRODUCTION: The incidence of impacted wisdom teeth (third molars) is high, with some 72% of Swedish people aged 20 to 30 years having at least one impacted wisdom tooth. Impacted wisdom teeth occur because of a lack of space, obstruction, or abnormal position. They can cause inflammatory dental disease manifested by pain and swelling of infected teeth and may destroy adjacent teeth and bone. METHODS AND OUTCOMES: We conducted a systematic review and aimed to answer the following clinical questions: Should asymptomatic, disease-free impacted wisdom teeth be removed prophylactically? What are the effects of different operative (surgical) techniques for removing impacted wisdom teeth? We searched: Medline, Embase, The Cochrane Library, and other important databases up to October 2013 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). We performed a GRADE evaluation of the quality of evidence for interventions. RESULTS: We found 11 studies that met our inclusion criteria. CONCLUSIONS: In this systematic review, we present information relating to the effectiveness and safety of the following interventions: prophylactic extraction, active surveillance, and different operative (surgical) techniques for extracting impacted wisdom teeth.

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.

Management of premature primary tooth loss in the child patient.

Premature loss of primary teeth can result in a loss of arch length and have a negative effect on occlusion and alignment, often increasing the need for orthodontic treatment. Use of space maintainers can reduce the severity of problems such as crowding, ectopic eruption, tooth impaction and poor molar relationship. This article presents a review of the consequences of premature tooth loss and discusses the appliances commonly used for space maintenance.

Interceptive therapy for maxillary constriction: a cast-metal-type splint expander.

A new cast-metal-type splint expander was used to treat severe maxillary constriction. This new appliance has the same advantages of a rapid expander on acrylic splints, compared to a Haas or to a banded expander. Furthermore, it is characterized by greater respect for the gingival tissue, both during the therapy and immediately after the removal of the expander. It is also more comfortable for the patient, so that it is possible to maintain the expander in the mouth for several months without gingival suffering. This appliance is very versatile and well indicated for permanent, mixed and deciduous dentitions.

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.

A controlled study on diagnostic and prognostic measurements of palatally displaced canines on lateral cephalograms.

OBJECTIVES: The aim of this prospective controlled study was to determine the role that the lateral cephalogram can play in the detection of palatally displaced canines (PDCs). MATERIALS AND METHODS: The study was comprised of 85 subjects in the late mixed dentition. Thirty-five subjects had PDCs (either unilateral or bilateral) identified on the panoramic radiograph (PDC group), and 50 subjects presented with a normal pathway of upper permanent canine eruption as assessed on panoramic radiographs (No-PDC group). Linear and angular measurements on the lateral cephalograms concurrent with panoramic radiographs were compared between the PDC and No-PDC group statistically. RESULTS: All angular measurements that incorporated the main axis of the canine (to Frankfort horizontal, to the palatal plane, or to the axis of the central incisor) were significantly smaller in the PDC group (p<0.001). In terms of linear measurements, both the distance from the tip of the canine to the vertical axis of the central incisor parallel to Frankfort horizontal and the distance from the tip of the canine to the anterior alveolar ridge parallel to Frankfort horizontal showed significantly larger values in the PDC subjects than in normal controls. On the contrary, the vertical distance from the tip of the canine to the functional occlusal plane did not reveal any significant difference between the PDC and the No-PDC group. CONCLUSIONS: Early diagnosis of PDC is essential in order to avoid the occurrence of final canine impaction. If 3-D images of a displaced canine cannot be acquired, a lateral cephalogram can be a useful tool for the early detection of PDC in the late mixed dentition. The angle between the vertical axis of the canine and the palatal plane demonstrate diagnostic value when assessing PDCs. Values for this angle smaller than 102 degrees can indicate the presence of PDC.

An RCT on treatment of palatally displaced canines with RME and/or a transpalatal arch.

AIM: To investigate the effect of rapid maxillary expansion (RME) and/or transpalatal arch (TPA) therapy in combination with deciduous canine extraction on the eruption of palatally displaced canines (PDCs). SUBJECTS AND METHODS: Hundred and twenty subjects were enrolled in an RCT based on PDCs diagnosed on panoramic radiographs and they were randomly assigned to one of four study groups. Three treatment groups (TGs) (RME followed by TPA therapy plus extraction of deciduous canines, RME/TPA/EC group, 40 subjects; TPA therapy plus extraction of deciduous canines, TPA/EC group, 25 subjects; extraction of deciduous canines, EC group, 25 subjects) were analyzed. A control group (CG, 30 subjects) received no orthodontic treatment. Prevalence rates of eruption of PDCs in the three TGs were compared with the CG at T2. Predictive features at T1 for successful canine eruption were tested in the three TGs. RESULTS AND DISCUSSION: The prevalence of canine eruption was 80 per cent for the RME/TPA/EC group, 79 per cent for the TPA/EC group, 62.5 per cent for the EC group, versus 28 per cent in the CG, with statistically significant differences between all the groups, with the exception of the comparison between RME/TPA/EC and TPA/EC. Predictive pretreatment variables for the success of treatment were less severe sectors of canine displacement, prepubertal stages of skeletal maturity, and an open root apex of PDCs. CONCLUSIONS: The use of a TPA in absence of RME can be equally effective than the RME/TPA combination in PDC cases not requiring maxillary expansion, thus reducing the burden of treatment for the patient.

A systematic review of the interceptive treatment of palatally displaced maxillary canines.

The aim of this study was to assess whether interceptive treatment in the mixed dentition prevents impaction of palatally displaced canines (PDC) by systematically reviewing the literature. A literature search of PubMed, the Cochrane Library electronic databases, and Scopus was performed covering the period from January 1966 to May 2009. The inclusion criteria were mixed dentition with unilateral or bilateral PDC, randomized controlled trials (RCT), prospective and retrospective studies with untreated controls, and clinical trials comparing at least two treatment strategies. Three reviewers selected and extracted the data independently and evaluated the quality of the studies. Inter-examiner reliability was measured using the intraclass correlation coefficient (ICC). The search strategy resulted in 686 articles, of which two met the inclusion criteria. Because of the unequivocal results and heterogeneity in the study methods, the scientific evidence was too weak to fully evaluate the effect that interceptive treatment might have on PDC and which treatment modalities are most effective. The quality of the studies was rated as low because of inadequate sample selection and deficient description of sample size, confounding factors, uncertainty of randominization, and no blinding in measurements. The ICC value for total scores was >0.80, e.g. perfect agreement. To obtain reliable scientific evidence as to whether interceptive treatment prevents impaction of PDC and which treatment modalities are the most effective, better controlled and well-designed RCTs are needed. Future studies should also include assessment of patient satisfaction and pain experience as well as analysis of the costs and side-effects of treatments.

Early identification and management of mandibular canine ectopia.

Mandibular canine impaction and transmigration have serious consequences for the patient, as removal of the tooth or teeth in question is often the only solution. The loss of one or both mandibular canines complicates orthodontic treatment. Early warning signs of mandibular canine ectopia are explored in this paper as well as how to assess the potential for displacement, impaction and/or transmigration. This paper highlights the value of interceptive treatment once the early signs of an aberrant mandibular canine have been detected.