Periodontitis en niños sanos de 3 años: dos casos con seguimiento a 5 años / Periodontitis in healthy 3-year-old children: two cases with 5-year follow-up

Objetivo: La periodontitis en dentición primaria es ex- cepcional en niños sin enfermedades sistémicas. El objetivo de este informe es describir las características clínicas y ra- diográficas de dos casos de niños de 3 años sistémicamente sanos con periodontitis, y su tratamiento con seguimiento a 5 años. Casos clínicos: En ambos casos, a los 3 años de edad los niños fueron derivados al especialista en periodoncia por su odontopediatra debido a la pérdida muy temprana de inci- sivos inferiores. El examen clínico y radiográfico mostró pér- dida de inserción clínica, pérdida ósea y movilidad dental en otros incisivos superiores e inferiores. Se realizó la intercon- sulta médica y se descartó que los niños padecieran enferme- dades relacionadas con el diagnóstico de periodontitis como manifestación de una enfermedad sistémica. El tratamiento consistió en la instrucción de medidas de higiene bucal que debían ser ejecutadas por los padres, ins- trumentación subgingival, antisépticos locales, medicación antibiótica sistémica y mantenimiento periodontal. No se rea- lizaron extracciones como parte del tratamiento. En ambos casos uno de los incisivos presentes al momento de la con- sulta se perdió prematuramente, antes de los 4 años. El resto de los incisivos primarios cumplieron su ciclo normal. Luego de 5 años de seguimiento, a la edad de 8 años, ambos niños presentaban los incisivos y los primeros molares permanentes periodontalmente sanos y el resto de los dientes primarios sin signos de periodontitis (AU)

Aim: Periodontitis in primary dentition is exceptional in children without systemic diseases. The objective of this article is to describe the clinical and radiographic charac- teristics of two cases of systemically healthy 3-year-old chil- dren with periodontitis, and their treatment, with a 5-year follow-up. Clinical cases: In both cases, at 3 years of age, the chil- dren were referred to a periodontic specialist by their pediat- ric dentist, due to the very early loss of lower incisors. Clin- ical and radiographic examination showed loss of clinical attachment, bone loss and dental mobility in other upper and lower incisors. A medical consultation was carried out and diseases related to the diagnosis of periodontitis as a mani- festation of a systemic disease were ruled out. The treatment consisted of instruction on oral hygiene measures that had to be carried out by the parents, subgingival instrumentation, local antiseptics, systemic antibiotic medication, and perio- dontal maintenance. No extractions were performed as part of the treatment. In both cases, one of the incisors present at the time of consultation was lost prematurely, before the age of 4 years. The rest of the primary incisors completed their normal cycle. After 5 years of follow-up, at the age of 8 years, both children showed periodontally healthy incisors and first permanent molars, and the rest of the primary teeth without signs of periodontitis (AU)

Analysis of Factors that Affect the Follow-up Pattern after Dental Treatment under Conscious Sedation in Children / 대한소아치과학회지

Children need regularly dental check-ups after dental treatment because there are a lot of changes of oral conditions such as tooth exfoliation and eruption, occlusion, and recurrence of dental caries. The purpose of this study is to determine the factors that affect the follow-up pattern after dental treatment under conscious sedation.Patients who were treated under sedation at the department of pediatric dentistry of Ewha Womans University Mokdong Hospital from 2009 to 2013 were included in this study. The final samples comprised of 562 patients that were classified into 4 groups according to the number of visits during 3 years. The chi-square test was used to determine the factors affecting regular follow-up.There were statistically significant differences between each treatment groups and factors such as the change of doctor, overall treatment time, the number of treated teeth under sedation, restorative treatment, minor operation, and preventive treatment (p < 0.05).This study identified factors that affect regular follow-up after dental treatment under conscious sedation. It is recommended to educate the importance of regular check-ups to parents who are less likely to return.

Indoleamine 2,3-dioxygenase is dispensable for the immunomodulatory function of stem cells from human exfoliated deciduous teeth

Objective: In this study, we sought to better understand the immunoregulatory function of stem cells derived from human exfoliated deciduous teeth [SHED]. We studied the role of the interferon gamma [IFN-gamma]-indoleamine 2,3-dioxygenase [IDO]-axis in immunoregulation of SHED compared to bone marrow derived mesenchymal stem cells [BMMSCs] under the same conditions

Materials and Methods: In this cross-sectional study, recently isolated human T cells were stimulated either by mitogen or inactivated allogeneic peripheral blood mononuclear cells [PBMCs]. These T cells were subsequently co-cultured with, either SHED or BMMSCs in the presence or absence of 1-methyl-tryptophan [1-MT] or neutralizing anti-human-IFN-gamma antibodies. In all co-cultures we evaluated lymphocyte activation as well as IDO activity

Results: SHED, similar to conventional BMMSCs, had anti-proliferative effects on stimulated T cells and reduced their cytokine production. This property of SHED and BMMSCs was changed by IFN-gamma neutralization. We detected IDO in the immunosuppressive supernatant of all co-cultures. Removal of IDO decreased the immunosuppression of BMMSCs

Conclusion: SHED, like BMMSCs, produced the IDO enzyme. Although IFN-gamma is one of inducer of IDO production in SHED, these cells were not affected by IFN-gamma in the same manner as BMMSCs. Unlike BMMSCs, the IDO enzyme did not contribute to their immunosuppression and might have other cell-type specific roles

Perfil de problemas orales en infantes y preescolares atendidos en el servicio de urgencias odontológicas de un centro de salud infantil de Brasil / Perfil de problemas orais em infantes e pré-escolares tratados no serviço de urgências odontológicas de um centro de saúde infantil do Brasil / Oral health problems profile in infants and preschool children attended at the dental emergency service of a children ́s health centre of Brazil

Objetivo: Determinar el perfil de los problemas orales en lactantes y preescolares atendidos en el servicio de urgencias de la Clínica de Especialidades infantil/ Clínica de Bebés de la Universidad Estatal de Londrina, Brasil. Materiales y métodos:Estudio retrospectivo donde se analizaron 776 historias clínicas de pacientes en el rango de edad de 0 a 72 meses, atendidos entre abril de 2007 a abril de 2008. Los datos recolectados fueron: Género, edad, lugar de residencia, ocupación y grado de escolaridad de los padres, motivo de consulta, dientes involucrados e intervenciones realizadas. Se utilizó la prueba de Chi2(χ2) y un nivel de significancia de 5% para la asociación entre variables. Resultados: Se observó una mayor proporción de pacientes de género masculino en la búsqueda del servicio (55,5%) y la mayoría de pacientes se ubicaron en el rango de edad de 0 a 24 meses (27,3%). Se verificó que el 62,9% residían en la zona urbana y la mayoría de los padres/responsables habían cursado secundaria completa (30,5% padres, 33,8% madres). Los motivos de consulta más frecuentes en la atención fueron caries dental (38,9%) siendo el dolor la queja principal (42,0%) y trauma dental (28,9%). Los dientes más afectados por caries fueron los segundos molares inferiores primarios y, por trauma los incisivos centrales superiores primarios. Dentro de las intervenciones más comunes se encontraron el tratamiento endodóntico (16,0%) y la adecuación del medio bucal (15,1%). Se encontró una asociación estadísticamente significativa entre escolaridad de la madre y motivo de consulta en el servicio de urgencias (p=0,001). Conclusión: El servicio analizado es necesario y útil, sin embargo, la resolución de problemas orales en la población infantil de Londrina, ocurrirá por medio de una reorganización de los servicios odontológicos actuales.

Objective: To determine the profile of oral problems in infants and preschool children treated at an emergency service from Clinic of Infantile Specialities / Clinical Baby of the State University of Londrina, Brazil. Materials and method: Retrospective study where 776 clinical histories of patients aged 0 to 72 months, treated between April 2007 and April 2008 were analysed. Data collection included gender, age, place of residence, parental occupation and educational level, reason for consultation, involved teeth and performed intervention. Chi-square test (χ2) and a significance level of 5% were used for variables associations. Results:A greater proportion of male patients (55.5%) attended the service and the main age group was the 0-24 months (27.3%). It was found that 62.9% lived in urban areas and most parents/caregivers had completed secondary school (30.5% parents, 33.8% mothers). The main reason for consultation was caries (38.9%) - pain as main complaint (42.0%) and dental trauma (28.9%). The most affected tooth by caries was the lower second primary molar and, regarding trauma, the upper central primary incisors were the most injured. Interventions varied from endodontic treatment (16.0%) and adequacy of oral environment (15.1%). There was a statistically significant association between mother educational level and reason for consultation (p = 0.001). Conclusion:The assessed health service was necessary and useful. However, oral health problems resolution in the paediatric population in Londrina will only occur after the implementation of reorganised dental services from the currently available.

Objetivo: Determinar o perfil dos problemas bucais em lactantes e pré-escolares atendidos no pronto socorro da Clínica de Especialidades Infantis / Bebê Clínica da Universidade Estadual de Londrina, Brasil. Materiais e métodos: Estudo retrospec-tivo onde foram analisados 776 prontuários odontológicos de pacientes na faixa etária de 0 a 72 meses, atendidos entre abril de 2007 a abril de 2008. Os dados coletados foram: Gênero, idade, lugar de moradia, ocupação e grau de escolaridade dos pais, motivo da consulta, dentes envolvidos e intervenções realizadas. Foi usado o teste qui-quadrado (χ2) e estabeleceu-se um nível de significância de 5% para a associação entre variáveis. Resultados: Observou-se uma maior proporção de pacientes de sexo masculino na procura do atendimento (55,5%) e a maioria dos pacientes pertenciam à faixa etária de 0 a 24 meses (27,3%). Verificou-se que, 62,9% moravam na zona urbana e a maioria dos pais/responsáveis possuíam escolaridade de segundo grau completo (30,5% pais, 33,8% mães). Os motivos mais frequentes pelo atendimento foram cárie dentária (38,9%) sendo a dor a principal queixa 42,0%, e trauma dentário (28,9%). Os dentes mais acometidos pela cárie foram os segundos molares infe-riores e por trauma, os incisivos centrais superiores decíduos. As intervenções mais comuns foram o tratamento endodôntico (16,0%) e adequação do meio bucal (15,1%). Houve associação estatisticamente significante entre escolaridade da mãe e moti-vo da consulta do pronto socorro (p=0,001). Conclusão: O serviço de urgência é necessário e útil, porém, a resolução dos pro-blemas bucais na população infantil de Londrina, ocorrerá por meio de uma reorganização dos serviços odontológicos atuais.

Effects of low-level laser therapy on stem cells from human exfoliated deciduous teeth

ABSTRACT Low-Level Laser Therapy stimulates the proliferation of a variety of types of cells. However, very little is known about its effect on stem cells from human exfoliated deciduous teeth (SHED). Objective This study aimed to evaluate the influence of different laser therapy energy densities on SHED viability and proliferation. Material and Methods SHED were irradiated according to the groups: I (1.2 J/cm2 - 0.5 mW – 10 s), II (2.5 J/cm2 – 10 mW – 10 s), III (3.7 J/cm2 – 15 mW – 10 s), IV (5.0 J/cm2 – 20 mW – 10 s), V (6.2 J/cm2 – 25 mW – 10 s), and VI (not irradiated – control group). Cell viability was assessed 6 and 24 h after irradiation measuring the mitochondrial activity and using the Crystal Violet assay. Cell proliferation was assessed after 24, 48, and 72 h of irradiation by SRB assay. Results MTT assay demonstrated differences from 6 to 24 hours after irradiation. After 24 h, groups I and IV showed higher absorbance values than those of control group. Crystal Violet assay showed statistically differences in the absorbance rate from 6 to 24 h after irradiation for groups III and VI. At 24 h after irradiation, Group III absorbance rate was greater than that of groups I, II, and IV. Group VI absorbance rate was greater than that of groups I and IV. SRB assay showed that the group I had higher rates than those of groups II, III, V, and VI, at 24 h after irradiation. After 48 h, group I exhibited the greatest cell proliferation rate followed by groups III, V, and VI. After 72 h, group III exhibited the lowest cell proliferation rate than those of groups II, IV, and V. Conclusions The Low-Level Laser Therapy energy densities used in this study did not cause loss of cell viability and stimulated SHED proliferation within the parameters described in this study.

Manejo de dientes natales y neonatales: reporte de dos casos / Management of natal and neonatal teeth: report of two cases

Los dientes natales son órganos dentarios que se presentan al nacimiento, y los neonatales son aquellos que erupcionan durante el primer mes de vida. La etiología exacta es desconocida. El manejo de estos dientes depende de múltiples factores. La extracción está indicada cuando eldiente es un supernumerario o presenta movilidad excesiva debido al riesgo de broncoaspiración. Cuando tienen ligera movilidad, generalmente se estabilizan conforme van erupcionando. El objetivo de este reporte es la presentación de dos casos clínicos de dientes natales yneonatales que se manejaron con abordajes diferentes, el primero demanera conservadora y el segundo con la extracción del órgano dental.

Natal teeth are those present at birth. Those erupting during the fi rst month of life are neonatal teeth. The etiology is not known. Natal teeth management is dependent on multiple factors. If the natal tooth is su-pernumerary, the treatment of choice is extraction; likewise, when the teeth are excessively mobile, extraction is indicated due to the risk of aspiration. When natal teeth are only slightly mobile, they often stabilize soon after eruption. The aim of this report is to present two cases of natal and neonatal teeth that were managed with different approaches; the fi rst with a more conservative treatment and the second one with the extraction of the teeth.

Human dental pulp stem cells transplantation combined with treadmill training in rats after traumatic spinal cord injury

Spinal cord injury (SCI) is a disabling condition resulting in deficits of sensory and motor functions, and has no effective treatment. Considering that protocols with stem cell transplantation and treadmill training have shown promising results, the present study evaluated the effectiveness of stem cells from human exfoliated deciduous teeth (SHEDs) transplantation combined with treadmill training in rats with experimental spinal cord injury. Fifty-four Wistar rats were spinalized using NYU impactor. The rats were randomly distributed into 5 groups: Sham (laminectomy with no SCI, n=10); SCI (laminectomy followed by SCI, n=12); SHEDs (SCI treated with SHEDs, n=11); TT (SCI treated with treadmill training, n=11); SHEDs+TT (SCI treated with SHEDs and treadmill training; n=10). Treatment with SHEDs alone or in combination with treadmill training promoted functional recovery, reaching scores of 15 and 14, respectively, in the BBB scale, being different from the SCI group, which reached 11. SHEDs treatment was able to reduce the cystic cavity area and glial scar, increase neurofilament. Treadmill training alone had no functional effectiveness or tissue effects. In a second experiment, the SHEDs transplantation reduced the TNF-α levels in the cord tissue measured 6 h after the injury. Contrary to our hypothesis, treadmill training either alone or in combination, caused no functional improvement. However, SHEDs showed to be neuroprotective, by the reduction of TNF-α levels, the cystic cavity and the glial scar associated with the improvement of motor function after SCI. These results provide evidence that grafted SHEDs might be an effective therapy to spinal cord lesions, with possible anti-inflammatory action.

Orthodontic movement in deciduous teeth

Deciduous teeth exfoliate as a result of apoptosis induced by cementoblasts, a process that reveals the mineralized portion of the root while attracting clasts. Root resorption in deciduous teeth is slow due to lack of mediators necessary to speed it up; however, it accelerates and spreads in one single direction whenever a permanent tooth pericoronal follicle, rich in epithelial growth factor (EGF), or other bone resorption mediators come near. The latter are responsible for bone resorption during eruption, and deciduous teeth root resorption and exfoliation. Should deciduous teeth be subjected to orthodontic movement or anchorage, mediators local levels will increase. Thus, one should be fully aware that root resorption in deciduous teeth will speed up and exfoliation will early occur. Treatment planning involving deciduous teeth orthodontic movement and/or anchorage should consider: Are clinical benefits relevant enough as to be worth the risk of undergoing early inconvenient root resorption?.

O dente decíduo é esfoliado graças à apoptose em seus cementoblastos, que desnuda a parte mineralizada da raiz e atrai os clastos. A rizólise é lenta, pois faltam mediadores em quantidade para acelerar o processo, mas ela se acelera e unidireciona quando se aproxima um folículo pericoronário de dente permanente rico em EGF e outros mediadores da reabsorção óssea - os responsáveis pelas reabsorções óssea na erupção e dentária decídua na rizólise e esfoliação. Se houver movimentação ortodôntica ou ancoragem em dentes decíduos, aumenta-se, também, o nível local desses mesmos mediadores, devendo-se estar bem consciente de que haverá uma aceleração da rizólise e, em decorrência, uma antecipação de sua esfoliação. No planejamento de casos em que dentes decíduos estejam envolvidos na movimentação ortodôntica e/ou ancoragem, deve-se ponderar: o benefício clínico para o paciente será relevante, a ponto de valer o risco de uma rizólise abreviada e inconveniente?.

Dental complications of herpes zoster: Two case reports and review of literature.

Herpes zoster (HZ) (shingles) results due to reactivation of varicella‑zoster virus. Unusual dental complications like osteonecrosis, exfoliation of teeth, periodontitis, and calcified and devitalized pulps, periapical lesions, and resorption of roots as well as developmental anomalies such as irregular short roots and missing teeth may arise secondary to involvement of 2nd or 3rd division of trigeminal nerve by HZ. Such cases pose both a diagnostic as well as a therapeutic challenge. We report two such rare dental complications of HZ‑spontaneous tooth exfoliation and osteonecrosis of the maxilla in a 70‑year‑old female patient; and multiple periapical pathoses affecting right half of the mandibular teeth in a 45‑year‑old female patient. Both the patients did not have any associated systemic illness. The aim of this paper was to compare the present cases with all the 46 cases of osteonecrosis and 6 cases of multiple periapical pathoses secondary to trigeminal zoster reported in literature till date The article also throws light that the occurrence of such dental complications of HZ is not entirely dependent on the immune status of the host.

Extracciones dentales atraumáticas en pacientes pediátricos con trastornos de la coagulación: descripción de la técnica y reporte de un caso / Atraumatic tooth extractions in pediatric patients with bleeding disorders: a technical description and report of a case

Se detalla y fundamenta la técnica de extracción atraumática de dientestemporales unirradiculares en pacientes pediátricos con trastornos de lacoagulación utilizando separadores elastoméricos. Se expone el caso deun paciente pediátrico con diagnóstico de defi ciencia de factor X de lacoagulación, quien requirió de la extracción atraumática de los órganosdentarios centrales superiores temporales debido a la gingivorragiapropia de la exfoliación natural.

We describe the technique of atraumatic tooth extraction for single-rooted temporary and permanent teeth in pediatric patients with bleed-ing disorders using elastomeric separators and discuss its benefi ts. We present the case of a pediatric patient diagnosed with coagulation factor X defi ciency who required the atraumatic extraction of his temporary upper central teeth due to gingival bleeding caused by natural exfoliation.

Chediak-Higashi Syndrome and Premature Exfoliation of Primary Teeth

The Chediak-Higashi syndrome (CHS) is a rare hereditary fatal disease, if not treated. These changes are associated with various diseases and syndromes that mainly cause periodontal disease and thus the premature loss of teeth. This paper describes the monitoring of premature loss of primary teeth that began when the child was 5 years old. On presentation his teeth were mobile and there was a history of gingival bleeding. Panoramic radiography revealed generalized and severe bone loss, and the teeth showed no bony support enough for their stability. Blood test was ordered to assess the overall health of the child and giant cells with cytoplasmic granules were found, confirming the diagnosis of CHS. The management of periodontal disease focused on the control of infection and bacterial plaque by mechanical and chemical methods.

A síndrome de Chediak-Higashi (CHS) é uma doença rara hereditária e fatal se não for tratada. Estas alterações estão associadas com várias doenças e síndromes que, principalmente, causa a doença periodontal assim como perda prematura de dentes. Este artigo descreve o monitoramento de perda prematura de dentes decíduos, que começou quando a criança tinha 05 anos. Na apresentação os dentes estavam com mobilidade e apresentava sangramento gengival. As radiografias panorâmicas revelaram perda óssea generalizada e grave, e os dentes sem suporte ósseo suficiente para a sua estabilidade. Foi realizada o exame de sangue para avaliar a saúde geral da criança no qual foi encontrado células gigantes com grânulos citoplasmáticos, confirmando o diagnóstico de CHS. O tratamento da doença periodontal por meio de métodos mecânicos e químicos são necessários para controle da infecção e da placa bacteriana.

Effect of chitosan on osteogenic properties of mesenchymal stem cell of exfoliated deciduous teeth

The exfoliated human deciduous tooth contains multipotent stem cells [Stem Cell from Human Exfoliated Deciduous tooth [SHED]] that identified to be a population of highly proliferative and clonogenic. These cells are capable of differentiating into a variety of cell types including osteoblast/osteocyte, adiopcyte, chondrocyte and neural cell. The aim of this study was to evaluate the differentiation of SHED to osteoblast in standard osteogenic medium and comparing the results with medium which supplemented with glucosamine in form of chitosan. Dental pulp cells were isolated from freshly extracted primary teeth, digested with 4 mg/ml collogenase/dispase, and grown in Dulbecco's modified Eagle's medium with 10 percent fetal bovine serum. The clonogenic potential of cells was performed after 3 weeks of culture. Flowcytometric analysis, performed at day 21 of culture to identify surface markers of mesenchymal stem cells. The cells from 3rd passage were used for osteogenic differentiation in routine osteoinductive medium. Chitosan [10 microg/ml] was added to the culture medium of case group. Alizarin Red Staining and Alkaline Phosphatase [ALP] activity were done to evaluate osteogenic differentiation in the developing adherent layer on the third passage. The results were analyzed using T-test. For the analysis of normal distribution of data, non-parametric Kolmogrov-Smirnov test was used. The colonogenic efficiency was more than 80%. Flowcytometric analysis showed that the expression of mesenchymal stem cell marker CD90, CD 105 and CD146 were positive in SHED, while hematopoietic cell marker CD34, CD45 and endothelial cell marker CD31 were negative. Quantitative analysis of Alizarin Red Staining demonstrated that: mineralized nodule formation was higher in the group supplemented with glucosamine [chitosan]. Results from Alkaline Phosphatase activity test, on day 21, demonstrated a significantly higher ALP activity in the group supplemented chitosan [P<0.001]. Stem cells isolated and cultured from exfoliated deciduous teeth pulp can be differentiated to osteoblast. Addition of chitosan can be beneficial to promote osteogenic differentiation of these cells

Alveolar bone necrosis and spontaneous tooth exfoliation associated with trigeminal herpes zoster: a report of three cases

Herpes zoster is a viral infection caused by the reactivation of the varicella zoster virus, an infection most commonly affecting the thoracolumbar trunk. Herpes Zoster Infection (HZI) may affect the cranial nerves, most frequently the trigeminal. HZI of the trigeminal nerve distribution network manifests as multiple, painful vesicular eruptions of the skin and mucosa which are innervated by the infected nerves. Oral vesicles usually appear after the skin manifestations. The vesicles rupture and coalesce, leaving mucosal erosions without subsequent scarring in most cases. The worst complication of HZI is post-herpetic neuralgia; other complications include facial scarring, motor nerve palsy and optic neuropathy. Osteonecrosis with spontaneous exfoliation of the teeth is an uncommon complication associated with HZI of the trigeminal nerve. We report several cases of osteomyelitis appearing on the mandible, caused by HZI, and triggering osteonecrosis or spontaneous tooth exfoliation.

The nance lingual arch: an auxiliary device in solving lower anterior crowding

After exfoliation of the primary incisors and eruption of the permanent incisors, the dentist has the opportunity of observing closely the beginning of occlusal changes. In several cases, alterations, such as lower anterior crowding, can be prevented and treated with proper follow-up. In the mixed dentition, one of the mechanisms for maintaining space and favoring dental alignment is to preserve leeway space before permanent second molar irruption. Among the devices with this function, the Nance lingual arch helps maintaining the position of the permanent mandibular molars and incisors after a premature loss of the primary canines. This paper describes the applicability of Nance lingual arch for preserving leeway space, thus contributing for correction of lower anterior crowding.

Após a esfoliação dos incisivos decíduos e a irrupção dos incisivos permanentes, o dentista tem a oportunidade de observar o início das alterações na oclusão. Em muitos casos, realizando o correto acompanhamento, pode-se prevenir e tratar possíveis más oclusões como o apinhamento anteroinferior. Na dentadura mista, um dos mecanismos para manter espaço e favorecer o alinhamento dentário consiste na preservação do espaço disponível de Nance (leeway space), antes da irrupção do segundo molar permanente. Dentre os dispositivos utilizados para esta finalidade, o arco lingual de Nance auxilia a manutenção do posicionamento dos molares permanentes e incisivos inferiores, quando da perda prematura dos caninos decíduos. Este trabalho objetiva descrever a aplicabilidade do arco lingual de Nance para a preservação do leeway space, o que contribuiu para a correção do apinhamento anteroinferior.

Mesenchymal stem cells in the dental tissues: perspectives for tissue regeneration

In recent years, stem cell research has grown exponentially owing to the recognition that stem cell-based therapies have the potential to improve the life of patients with conditions that range from Alzheimer’s disease to cardiac ischemia and regenerative medicine, like bone or tooth loss. Based on their ability to rescue and/or repair injured tissue and partially restore organ function, multiple types of stem/progenitor cells have been speculated. Growing evidence demonstrates that stem cells are primarily found in niches and that certain tissues contain more stem cells than others. Among these tissues, the dental tissues are considered a rich source of mesenchymal stem cells that are suitable for tissue engineering applications. It is known that these stem cells have the potential to differentiate into several cell types, including odontoblasts, neural progenitors, osteoblasts, chondrocytes, and adipocytes. In dentistry, stem cell biology and tissue engineering are of great interest since may provide an innovative for generation of clinical material and/or tissue regeneration. Mesenchymal stem cells were demonstrated in dental tissues, including dental pulp, periodontal ligament, dental papilla, and dental follicle. These stem cells can be isolated and grown under defined tissue culture conditions, and are potential cells for use in tissue engineering, including, dental tissue, nerves and bone regeneration. More recently, another source of stem cell has been successfully generated from human somatic cells into a pluripotent stage, the induced pluripotent stem cells (iPS cells), allowing creation of patient- and disease-specific stem cells. Collectively, the multipotency, high proliferation rates, and accessibility make the dental stem cell an attractive source of mesenchymal stem cells for tissue regeneration. This review describes new findings in the field of dental stem cell research and on their potential use in the tissue regeneration.

Nos últimos anos, as pesquisas com células tronco têm aumentado exponencialmente devido ao reconhecimento de que seu potencial terapêutico pode melhorar a qualidade de vida de pacientes com diversas doenças, como a doença de Alzheimer, isquemias cardíacas e, até mesmo, nas pesquisas de medicina regenerativa que visa uma possível substituição de órgão perdidos, como por exemplo, os dentes. Baseado em habilidades de reparar tecidos injuriados e restaurar parcialmente as funções de um órgão, diversos tipos de células-tronco têm sido estudadas. Recentes evidências demonstram que as células-tronco são primariamente encontradas em nichos e que certos tecidos apresentam mais células-tronco que outros. Entre estes, os tecidos dentais são considerados como uma fonte rica de células-tronco mesenquimais adequado para aplicações em engenharia tecidual. Sabe-se que estas células têm o potencial de diferenciarem-se em diversos tipos celulares, incluindo osteoblastos, células progenitoras de neurônios, osteoblastos, condrócitos e adipósitos. Na odontologia, a biologia celular e a engenharia tecidual são de grande interesse, pois fornecem inovações na geração de novos materiais clínicos e ou na regeneração tecidual. Estas podem ser isoladas e crescidas em diversos meios de cultura apresentando grande potencial para ser usada na engenharia tecidual, incluindo regeneração de tecidos dentais, nervos e ossos. Recentemente, outra fonte de células tronco tem sido geradas a partir de células somáticas de humanos a um estágio de pluripotência, chamados de células-tronco pluripotente induzida (iPS) levando à criação de células-tronco específicas. Coletivamente, a multipotencialidade, altas taxas de proliferação e acessibilidade, faz das células-tronco dentárias uma fonte atrativa de células-tronco mesenquimais para regeneração tecidual. Esta revisão descreve novos achados no campo da pesquisa com células-tronco dentais e seu potencial uso na regeneração tecidual.

Mecanismos celulares e moleculares envolvidos na reabsorção radicular fisiológica de dentes decíduos / Cellular and molecular mechanisms involved in the physiological root resorption of primary teeth

Introdução: A reabsorção fisiológica dos dentes decíduos constitui um fenômeno fisiológico complexo não completamente conhecido; assunto de grande interesse clínico. Os mecanismos celulares e moleculares envolvidos no fenômeno de reabsorção radicular fisiológica parecem ser similares aos mecanismos envolvidos na reabsorção óssea, mediada por osteoclastos. As principais células responsáveis pela reabsorção ativa dos tecidos dentais são os odontoclastos, também denominados de clastos ou osteoclastos; células gigantes multinucleadas originadas de precursores hematopoiéticos de monócitos ou macrófagos. Avanços recentes na literatura específica têm mostrado que a diferenciação e atividade dos osteoclastos, fenômeno também conhecido como osteoclastogênese, são iniciadas e reguladas por diferentes estímulos e sinalizadores moleculares como as citocinas, quimiocinas, produtos de degradação liberados pela superfície radicular afetada, moléculas de adesão, metaloproteinases e pelo sistema RANK/RANKL/OPG. Ainda, o contato físico entre os precursores de osteoclastos e osteoblastos ou células estromais também parece ser necessário para a ativação da osteoclastogênese. Entretanto, o papel específico dos fatores envolvidos no início e modulação da reabsorção radicular dos dentes decíduos permanece desconhecido. Objetivo: Realizar uma revisão de literatura sobre os mecanismos celulares e moleculares envolvidos no processo de reabsorção fisiológica dos dentes decíduos, enfatizando suas implicações clínicas.

Conclusão: Uma complexa interação entre osteclastos, osteoblastos, macrófagos, citocinas, quimiocinas, metaloproteinases, moléculas de adesão e o sistema RANK/RANKL/OPG parecem contribuir para a reabsorção dentária fisiológica. O conhecimento dos mecanismos celulares e moleculares envolvidos no processo de reabsorção fisiológica dos dentes decíduos pode contribuir para o estudo da imunopatogenia das reabsorções dentárias e futuramente resultar na aplicação clínica de mediadores moleculares para atrasar ou mesmo inibir esse processo

Introduction: The physiological resorption of primary teeth is a complex physiological phenomenon that is not completely known and is a subject of great interest. The cellular and molecular mechanisms involved in the phenomenon of physiological root resorption seem to be similar to those involved in bone resorption mediated by osteoclasts. The main cells responsible for the active resorption of the dental tissues are the odontoclasts, which are also known as clasts or osteoclasts; multi nucleated giant cells originated from hematopoietic precursors of monocytes or macrophages. Recent advances published in the literature have shown that the differentiation and activity of osteoclasts, a phenomenon that is also known as osteoclastgenesis, are initiated and regulated by different stimuli and molecular signalizing agents such as cytokines, chemokines, products of degradation released by the affected root surface, adhesion molecules, metalloproteinases, and the RANK/RANKL/OPG system. Moreover, the physical contact between the osteoclasts and osteoblast precursors or stromal cells also seems to be necessary for the activation of osteoclastgenesis. However, the specific role of the factors involved in the initiation and modulation of root resorption of the primary teeth remains unknown. Objective: To perform a review of the literature about the cellular and molecular mechanisms involved in the process of physiological resorption of the primary teeth, emphasizing their clinical implications.

Conclusion: A complex integration among osteoclasts, osteoblasts, macrophages, cytokines, chemokines, metalloproteinases, adhesion molecules and the RANK/RANKL/OPG system seems to contribute to the physiological resorption of teeth. Knowing the cellular and molecular mechanisms involved in the process of physiological root resorption of primary teeth may contribute to the investigation of the immunepathogenesis of dental resorptions, and allow for the clinical application of molecular mediators to delay or even inhibit this process

Do the origins of primary teeth affect the bond strength of a self-etching adhesive system to dentin?

The aim of this in vitro study was to evaluate the tensile bond strength of a self-etching adhesive system to three different dentinal substrates. Primary molar teeth that had been recently exfoliated (RE), with unknown time of exfoliation (UT), and extracted due to prolonged retention (PR) were used for this investigation. Ten primary molar teeth of each group were cut in the middle following the mesio-distal direction, creating a total of twenty specimens per group. The specimens were included in acrylic resin and had a flat dentin surface exposed. The self-etching adhesive system was applied to this surface and a 3-millimeter high cone with diameter of 2 mm in the adhesion area was constructed using composite resin. The specimens were stored in distilled water at 37ºC for 24 hours. Fifteen specimens of each substrate were used for the tensile bond test (n = 15) and 5 had the interface analyzed by scanning electron microscopy (SEM). The data was examined by one-way ANOVA and presented no significant differences between groups (p = 0.5787). The mean values obtained for RE, UT and PR were 18.39 ± 9.70, 19.41 ± 7.80, and 23.30 ± 9.37 MPa, respectively. Any dentinal substrates of primary teeth studied are safe for tensile bond strength tests with adhesive systems.

A scanning electron microscopic study of the patterns of external root resorption under different conditions

OBJECTIVE: The aim of this study was to examine if there are qualitative differences in the appearance of external root resorption patterns of primary teeth undergoing physiologic resorption and permanent teeth undergoing pathological root resorption in different conditions. MATERIAL AND METHODS: A total of 40 teeth undergoing external root resorption in different conditions were divided into 4 groups and prepared for examination under scanning electron microscopy at magnifications ranging from 20x to 1000x. Group I: 10 primary molars exfoliated due to physiologic root resorption; Group II: 10 permanent teeth with periapical granulomas showing signs of resorption; Group III:10 permanent teeth therapeutically extracted during the course of orthodontic therapy with evidence of resorption, and Group IV: 10 permanent teeth associated with odontogenic tumors that showed evidence of resorption. RESULTS: In Group I, the primary teeth undergoing resorption showed smooth extensive and predominantly regular areas reflecting the slow ongoing physiologic process. In Group II, the teeth with periapical granulomas showed the resorption was localized to apex with a funnel shaped appearance in most cases. Teeth in Group III, which had been subjected to a short period of light orthodontic force, showed the presence of numerous resorption craters with adjoining areas of cemental repair in some cases. Teeth associated with odontogenic tumors in Group IV showed many variations in the patterns of resorption with extensive loss of root length and a sharp cut appearance of the root in most cases. CONCLUSION: Differences were observed in the patterns of external root resorption among the studied groups of primary and permanent teeth under physiologic and pathological conditions.

Delayed Exfoliation of Primary Teeth Due to Second Pathoses: Case Series Study

The delayed exfoliation of primary teeth among children is a common and frequent dental problem whose most sited cause is misalignment of the crown of the successional permanent tooth with the root apex of the primary tooth. Treatment is often extraction of the over retained primary teeth and reassurance of the guardian that the normal tongue movements will push the misaligned permanent successional teeth into line in cases of mild misalignment or orthodontic treatment in severe cases of misalignment. However; meticulous history taking and careful clinical oral examination may yield an underlying pathosis as the three cases in this study illustrate. Underlying second pathoses may exert local and systemic effects on the normal exfoliative mechanism resulting in over retention of primary teeth despite proper alignment of the crown of the permanent successional tooth with the root apex of the primary tooth

A Clinical Case of Unilateral Maxillary Defect Reconstruction Using Nasolabial Flap