Mesenchymal Stem Cell Therapy for Treatment of Craniofacial Bone Defects: 10 Years of Experience

Introduction: Cell delivery in treatment of bone defects has been introduced to promote tissue healing in the recent years. However, no general consensus has been reached regarding the outcome of regenerative medicine for this purpose. The aim of this study was to review our 10 years of experience in application of mesenchymal stem cells (MSCs) in craniofacial bone defects. Applied Methodology: Iliac bone marrow, dental pulp and buccal fat pad were selected to harvest MSCs. Flow cytometric analysis, RT-PCR and differentiation staining including Alizarin red, Oil Red O and Toluidine blue were used to identify MSCs. Four groups of bone substitutes were used for cell delivery: synthetic scaffold [beta-tricalcium phosphate (B-TCP) and hydroxyapatite/tricalcium phosphate (HA/TCP)], xenograft [natural bovine bone mineral (NBBM)], allograft [freeze-dried bone (FDBA), demineralized freeze dried bone] and composite [polycaprolactone/TCP (PCL-TCP), demineralized freeze-dried bone/calcium sulfate]. Rat and rabbit calvaria, dog mandible, rabbit tibia sinus and alveolar cleft defects in human were used as the study models. Histomorphometric and radiomorphological analysis were used to determine new bone formation. Outcomes: Cell-treated groups showed greater new bone formation than cell-free group in all studies. Synthetic scaffolds showed better cell attachment according to scanning electron microscopy (SEM) results. In rat calvarial model, B-TCP loaded with MSCs showed better results than scaffolds carrying platelet rich plasma (PRP). NBBM showed less promising results both in dog mandible and ectopic bone formation in the masseter muscle. FDBA block fixed over a supracrestal defect in dog mandible showed 50% less new bone formation when compared with PCL-TCP as a carrier. Conclusion: More convergence studies with similar protocols of cell cultivation, culture, seeding and delivery should be done in the field of regenerative medicine for better generalizability of results for clinical setting.Keywords: Mesenchymal stem cells; Bone regeneration; Tissue engineering; Craniofacial bon

Bone Tissue Engineering: A Literature Review

Introduction: Classic bone tissue engineering involves use of osteogenic cells, growth factors, and bone scaffolds to generate a graft material to replace the gold standard which is autogenous bone graft. Several modifications have been applied to the classic approach but none of them can fully regenerate bone defects. The current study reviewes the literatures in applications of bone tissue engineering both in vivo and in vitro. Materials and Methods: An electronic search in MEDLINE was conducted and both in vivo and in vitro studies were included using bone scaffolds with or without osteogenic growth factors or stem cells. In vitro studies which did not investigate cell-scaffold interactions and in vivo studies which did not measure new bone formation were excluded. Results: Of 86 studies, 38 concerned in vitro and 48 in vivo studies. These studies were divided into six groups based on scaffold which they used: Synthetic, natural, polymers (non-ceramics), composites (polymer+ceramic), metal-based and nano-scaffolds. The results of the studies were compared in a qualitative manner. In vitro studies were mostly conducted on polymers, while relatively more animal and clinical studies were performed on ceramics. The most commonly used scaffolds, stem cells and growth factor were synthetic ceramics, bone marrow stem cells and bone morphgenic protein 2, respectively. Conclusion: Determination of the most successful approach was not possible due to the presence of several variable and variances in analyzing methods and data report. However, studies which used all three components of BTE, including scaffolds, growth factors and stem cells, showed good results both in vitro and in vivo

Failure Rate of Pediatric Dental Treatment under General Anesthesi

Aim: To assess the failure rates of various pediatric dental treatments performed under general anesthesia (GA) after six months to five years of follow-up. Design: This multicenter retrospective cohort study was performed on patients treated by five pedodontists in two private hospitals located in northern Iran during 2010⁻2013 and comprised 155 patients. The patients were recalled and clinically examined. During the clinical examination of the primary teeth, oral hygiene, dmft index, and failure of previous treatments was evaluated. The data were analyzed using the Chi square and regression analyses with a significance level of 0.05. Results: 114 patients (74 males and 40 females, mean age: 37.17 ± 10.75 months) with 1155 primary teeth treated under GA participated in the follow-up. The overall failure rate was 6.59%. The failure rates of pulpectomy, pulopotomy, fissure sealant, stainless steel crown (SSC), amalgam, and composite fillings were 2.90%, 3.03%, 4.83%, 5.26%, 5.33%, and 9.63%, respectively. Among the confounding factors, only gender had a significant effect on the anterior composite failure rate (p = 0.029) and age had a significant effect on the failure rate of fissure sealant therapy (p = 0.015) and SSC (p = 0.018). Conclusion: The overall rate of treatment failure in pediatric patients, treated under GA, was 6.59%

Bilateral Keratocystic Odontogenic Tumor Invading Maxillary Sinuses: A Case Report

Keratocystic odontogenic tumor (KCOT) is an odontogenic tumor which has the highest rate of recurrence. This report describes a rare case of bilateral ciliated epithelium-lined odontogenic keratocyst in the maxilla of a 15-year-old male. Panoramic radiography showed two lytic lesions on both sides of the maxilla associated with impacted third molars. Computerized tomography image revealed the involvement of both maxillary sinuses by the lesion which was destroying both sinuses’ floors and posterior walls. Histopathologically, the keratinized epithelial-lined cyst of OKC was changed to a ciliated columnar hyperchromatic epithelium, suggesting the fusion of both these epithelia rather than a metaplastic transformation. The patient was treated by surgical enucleation of the cyst and was followed for one year. In this case report the biological behaviour of odontogenic keratocysts and its treatment options are discussed

Asociación de los polimorfismos P561T y C422F del gen receptor de la hormona del crecimiento con dimensiones faciales.

Background: Growth hormone plays a significant role in determining craniofacial morphology. Mutations of its receptor gene might be associated with mandibular prognathism (MP). Purpose: The aim of the current study was to evaluate growth hormone receptor (GHR) gene polymorphisms in relation to facial dimensions. Material and Method: The study enrolled 65 participants with class III profile in MP group and 60 orthognathic control participants. Genomic DNA was extracted from a blood sample from the patients and the P561T and C422F polymorphisms of GHR gene were screened by PCR-RFLP method followed by Sanger sequencing of randomly selected samples to validate the genotyping results. Chi square was used to compare distribution of polymorphism in MP and control groups (p<0.05). Results: Heterozygous P561T mutation was found in 10.77% and 8.33% of MP and control groups, respectively (p=0.644) while none of the subjects had the C422F mutation. Sanger sequencing confirmed the genotyping results from the PCR-RFLP method. P561T polymorphism was significantly associated with ramus and lower facial height in MP patients and with ramus height in orthognathic patients (p<0.05). Conclusion: The results indicate that the P561T polymorphism of the GHR gene is associated with the vertical dimension of the mandible in an Iranian population.Antecedentes: La hormona del crecimiento desempeña un papel importante en la determinación de la morfología craneofacial. Las mutaciones de su gen receptor podrían estar asociadas con el prognatismo mandibular (PM). Propósito: El objetivo del presente estudio fue evaluar dos polimorfismos del gen del receptor de la hormona del crecimiento (RHC) en relación con las dimensiones faciales. Materiales y Métodos: El estudio incluyó a 65 participantes con perfil de clase III en el grupo MP y 60 participantes de control ortognático. El ADN genómico se extrajo de una muestra de sangre de los pacientes y los polimorfismos P561T y C422F del gen RHC se seleccionaron mediante el método PCR-RFLP seguido de la secuenciación por Sanger de muestras seleccionadas al azar para validar los resultados del genotipo por RFLP. El test chi cuadrado se utilizó para comparar la distribución del polimorfismo en el grupo MP y grupo control (p<0.05).Resultados: Se encontró mutación heterocigota P561T en 10.77% y 8.33% de los grupos PM y control, respectivamente (p=0.644) mientras que ninguno de los sujetos tenía la mutación C422F. La secuenciación de Sanger confirmó los resultados de genotipado por el método PCR-RFLP. El polimorfismo P561T se asoció significativamente con la rama y la altura facial más baja en pacientes con PM y con la altura de la rama en pacientes ortognáticos (p<0.05). Conclusión: Los resultados indican que el polimorfismo P561T del gen RHC está asociado con la dimensión vertical de la mandíbula en una población iraní

Preventive Effect of Professional Fluoride Supplements on Enamel Demineralization in Patients Undergoing Fixed Orthodontic Treatment: A Systematic Review and Meta-Analysis

Objective: The current study aimed to systematically review the randomized clinical trials assessing the preventive effect of professional fluoride interventions on enamel demineralization in patients undergoing fixed orthodontic treatment.Methods: The electronic search was performed in PubMed and Cochrane library in September 2021. No restriction was set on the publication date. Randomized clinical trials assessing the preventive effect of fluoride varnish, gel, mouthwash, and high-fluoride toothpaste on white spot lesions compared to the control group by clinical or radiographic methods in more than 10 patients were included.Results: A total of 7 articles consisting of 1418 participants were included. In 4 articles, fluoride varnish (contained a range of 1000-50 000 ppm fluoride) was applied multiple times (4-20 times) in test groups. Their results indicated that the test groups significantly had lesser new white spot lesions or advanced white spot lesions. One study used fluoride varnish only once at the beginning of treatment and reported no significant difference in white spot lesions compared to the control group. Application of high-fluoride toothpaste as well as fluoride mouthwash, also, showed significantly lower white spot lesions. Three studies were included in the meta-analysis and revealed that the relative risk of white spot lesions was 0.64 (95% CI = 0.40 to 0.89; P < .01) in favor of fluoride varnishConclusion: Multiple applications (4-20 times) of fluoride varnish or daily use of fluoride mouthwash or high-fluoride toothpaste seem to reduce white spot lesions in patients undergoing orthodontic treatment. However, single use of fluoride varnish was not effective. Further research is needed to establish the required number of fluoride applications for the prevention of white spot lesions during orthodontic treatment

Failure Rate of Pediatric Dental Treatment under General Anesthesia

Aim: To assess the failure rates of various pediatric dental treatments performed under general anesthesia (GA) after six months to five years of follow-up. Design: This multicenter retrospective cohort study was performed on patients treated by five pedodontists in two private hospitals located in northern Iran during 2010&ndash;2013 and comprised 155 patients. The patients were recalled and clinically examined. During the clinical examination of the primary teeth, oral hygiene, dmft index, and failure of previous treatments was evaluated. The data were analyzed using the Chi square and regression analyses with a significance level of 0.05. Results: 114 patients (74 males and 40 females, mean age: 37.17 &plusmn; 10.75 months) with 1155 primary teeth treated under GA participated in the follow-up. The overall failure rate was 6.59%. The failure rates of pulpectomy, pulopotomy, fissure sealant, stainless steel crown (SSC), amalgam, and composite fillings were 2.90%, 3.03%, 4.83%, 5.26%, 5.33%, and 9.63%, respectively. Among the confounding factors, only gender had a significant effect on the anterior composite failure rate (p = 0.029) and age had a significant effect on the failure rate of fissure sealant therapy (p = 0.015) and SSC (p = 0.018). Conclusion: The overall rate of treatment failure in pediatric patients, treated under GA, was 6.59%

Effect of Bracket Base Sandblasting on Bonding of Orthodontic Brackets on Enamel Surface

Introduction: In evaluating bond failure, considerable attention has been paid to the various factors that affect bond strength. The bracket–resin interface is the site of usual bond failure. Therefore, many efforts have been accomplished on this interface. The aim of this study was to compare the effects of sandblasting on shear bond strength of three different metal brackets. Materials and Methods: For this experimental study, 180 human maxillary first and second premolars teeth were cleaned and stored in 0.1% thymol solution. The teeth were randomly assigned to either the control (n = 90) or experimental group (n = 90). Each group was subdivided into three equal groups (n = 30). In the control group, three different non-sandblasted metal brackets (American Orthodontics, Dentarum, and 3M Unitek) were bonded with 3M (Unitek) no-mix resin. In the next stage of the experiment, similar brackets were sandblasted and bonded. All samples were pumiced and etched with 37% phosphoric acid for 15 s. The teeth were embedded in blocks of autopolymerization polymethyl methacrylate, utilizing a special device to make their slots parallel to the horizontal. Samples were stored in distilled water for 24 h before testing. Shear bond testing was carried out with UTM Instron machine. Results: Mean shear bond strength of untreated groups was 15.51, 16.60, and 18.58 MPa for American Orthodontics, Dentarum, and 3M Unitek brackets, respectively. Mean shear bond strength of sandblasted brackets was 15.8, 19.36, and 18.66 for American Orthodontics, Dentarum, and 3M Unitek brackets, respectively. Conclusion: This study showed that there was a significant difference in the mean shear bond strength between untreated and sandblasted specimens only in the Dentarum bracket groups