Effect of micro-osteoperforations on the gene expression profile of the periodontal ligament of orthodontically moved human teeth.

OBJECTIVES: This study aimed to evaluate the effect of micro-osteoperforations (MOPs) on the gene expression profile of the periodontal ligament (PDL) of orthodontically moved teeth. MATERIALS AND METHODS: Fifteen participants were randomly assigned into two groups: tooth movement only (Tr1, n = 7) and tooth movement supplemented with MOPs (Tr2, n = 8). In each subject, orthodontic tooth movement (OTM) was performed on premolar in one side, while no force was applied on contralateral premolar (Unt, n = 15). Seven days after loading, premolars were extracted for orthodontic reasons. RNA extraction from PDL and subsequent RNA-sequencing were performed. False discovery rates (Padj < 0.05) and log2 fold change (+ / - 1.5) thresholds were used to identify sets of differentially expressed genes (DEGs) among the groups. DEGs were analyzed with gene ontology enrichment, KEGG, and network analysis. RESULTS: Three hundred thirty-one DEGs were found between Tr1 and Unt, and 356 between Tr2 and Unt. Although, there were no significantly DEGs between Tr2 and Tr1, DEGs identified exclusively in Tr1 vs. Unt were different from those identified exclusively in Tr2 vs. Unt. In Tr1, genes were related to bone metabolism processes, such as osteoclast and osteoblast differentiation. In Tr2, genes were associated to inflammation processes, like inflammatory and immune responses, and cellular response to tumor necrosis factor. CONCLUSIONS: MOPs do not significantly alter the PDL gene expression profile of orthodontically moved human teeth. This study provides for the first time evidence on the whole PDL gene expression profiles associated to OTM in humans. Novel biomarkers for OTM are suggested for additional research. Clinical relevance The identified biomarkers provide new insights into the molecular mechanisms that would occur when OTM is supplemented with MOPs. These markers are expected to be useful in the near future for the application of personalized strategies related to the OTM.

Escobar Syndrome-An Multidisciplinary Approach for an Excellent Outcome With 3 Years of Follow-Up.

This case report intends to provide the facial characteristics of Escobar syndrome and to describe the orthodontic treatment of a 12-year-old female patient diagnosed with it. Escobar syndrome, a variant of the multiple pterygium syndrome, is a rare disorder with many systemic, facial, and oral manifestations.The patient presented with mixed dentition, severe dolichofacial pattern, increased lower facial height, convex profile, severe anterior open bite, maxillary hypoplasia, and mandibular retrognatism. The multidisciplinary approach included soft cleft palate repair, orthodontic treatment, orthognathic surgery, restorative cosmetic dentistry, speech therapy, and physiotherapy. Despite the limitations imposed by the syndrome, this report illustrates how the multidisciplinary treatment approach aided in the correction of occlusal function and facial esthetics and improvement in the quality of life of the patient with Escobar syndrome.

What are the advantages of living in a community? A microbial biofilm perspective!

Biofilm formation is the preferred mode of growth lifestyle for many microorganisms, including bacterial and fungal human pathogens. Biofilm is a strong and dynamic structure that confers a broad range of advantages to its members, such as adhesion/cohesion capabilities, mechanical properties, nutritional sources, metabolite exchange platform, cellular communication, protection and resistance to drugs (e.g., antimicrobials, antiseptics, and disinfectants), environmental stresses (e.g., dehydration and ultraviolet light), host immune attacks (e.g., antibodies, complement system, antimicrobial peptides, and phagocytes), and shear forces. Microbial biofilms cause problems in the hospital environment, generating high healthcare costs and prolonged patient stay, which can result in further secondary microbial infections and various health complications. Consequently, both public and private investments must be made to ensure better patient management, as well as to find novel therapeutic strategies to circumvent the resistance and resilience profiles arising from biofilm-associated microbial infections. In this work, we present a general overview of microbial biofilm formation and its relevance within the biomedical context.

Conservative approach for a patient with extreme delay in maxillary lateral incisor development.

The purpose of this article is to report the orthodontic treatment of a patient with extremely delayed development of the maxillary lateral incisors. At 7 years of age, the boy's permanent maxillary lateral incisors had not erupted. A radiograph showed no tooth germs in place, although well-defined radiolucent areas were evident. Removal of the radiolucent areas was contemplated, but it was rejected in favor of a conservative approach. At age 13, peg-shaped maxillary lateral incisors erupted; they were positioned during orthodontic treatment and reshaped with composite restorations, providing good esthetics and function.

FGF10 and FGF13 genetic variation and tooth-size discrepancies.

OBJECTIVES: To explore whether variations in odontogenesis-related genes are associated with tooth-size discrepancies. MATERIALS AND METHODS: Measurements of the width of permanent teeth were obtained from dental casts of 62 orthodontic patients (age 15.65 ± 6.82 years; 29 males and 33 females). Participants were classified according to the anterior and overall Bolton ratios as without tooth-size discrepancy or with maxillary or mandibular tooth-size excess. Genomic DNA extracted from buccal cells was used, and 13 single nucleotide polymorphisms (SNPs) across nine genes were genotyped by polymerase chain reaction using TaqMan chemistry. χ2 or Fisher exact tests were applied to determine the overrepresentation of genotypes/alleles depending on the type of tooth-size discrepancy (α = .05; corrected P value: P < 5.556 × 10-3). Odds ratios (ORs) and their correspondent 95% confidence intervals (CIs) were also calculated to investigate the risk of this phenotype for the SNPs having significant association. RESULTS: Individuals carrying the FGF10 rs900379 T allele were more likely to have larger mandibular teeth (OR = 3.74; 95% CI: 1.65-8.47; P = .002). This effect appeared to be stronger when two copies of the risk allele (TT) were found (recessive model, OR = 6.16; 95% CI: 1.71-22.16; P = .006). On the other hand, FGF13 rs5931572 rare homozygotes (AA, or male A hemizygotes) had increased risk of displaying tooth-size discrepancies when compared with the common homozygotes (GG, or male G hemizygotes; OR = 10.32; 95% CI: 2.20-48.26; P = .003). CONCLUSIONS: The results suggest that FGF10 and FGF13 may contribute to the presence of tooth-size discrepancies.

New SHH and Known SIX3 Variants in a Series of Latin American Patients with Holoprosencephaly.

Holoprosencephaly (HPE) is the failure of the embryonic forebrain to develop into 2 hemispheres promoting midline cerebral and facial defects. The wide phenotypic variability and causal heterogeneity make genetic counseling difficult. Heterozygous variants with incomplete penetrance and variable expressivity in the SHH, SIX3, ZIC2, and TGIF1 genes explain ∼25% of the known causes of nonchromosomal HPE. We studied these 4 genes and clinically described 27 Latin American families presenting with nonchromosomal HPE. Three new SHH variants and a third known SIX3 likely pathogenic variant found by Sanger sequencing explained 15% of our cases. Genotype-phenotype correlation in these 4 families and published families with identical or similar driver gene, mutated domain, conservation of residue in other species, and the type of variant explain the pathogenicity but not the phenotypic variability. Nine patients, including 2 with SHH pathogenic variants, presented benign variants of the SHH, SIX3, ZIC2, and TGIF1 genes with potential alteration of splicing, a causal proposition in need of further studies. Finding more families with the same SIX3 variant may allow further identification of genetic or environmental modifiers explaining its variable phenotypic expression.

Palatal configuration in Class II Division 1 malocclusion: a longitudinal study.

INTRODUCTION: The purpose of this study was to evaluate palatal contours in nonextraction orthodontic treatment and long-term stability in patients with Class II Division 1 malocclusions. METHODS: Data were obtained from maxillary study models before treatment, after treatment, and at least 5 years postretention. Data were collected with a digital pantograph in the canine, second premolar, and first molar regions. Palatal width, base width, palatal height, and alveolar angle were evaluated. RESULTS: During treatment, the canine region was stable; in the premolar and molar regions, there were statistically significant increases in transverse (palatal and base widths) and palatal height measurements, whereas the alveolar angle decreased. In the postretention evaluation, the canine region showed the greatest modifications, except for alveolar angulation, which was stable. The premolar region showed stability, but, in the molar region, palatal width and alveolar angulation decreased. CONCLUSIONS: In analyzing alterations in the geometry of palatal configuration, we concluded that a favorable transverse gain of the palatal base, from growth or orthodontics, was important for stability. The transverse gain of palatal base width during Class II treatment is important to compensate for the expected transverse loss in the cervical region and the decrease of alveolar angle in the long term.

Natural changes of the maxillary first molars in adolescents with skeletal Class II malocclusion.

INTRODUCTION: The objective of this study was to evaluate natural changes in maxillary posterior alveolar height (MPAH) and axial inclination of the maxillary first molars (AIMFM) in subjects with Class II malocclusion to determine the validity of predictive equations. METHODS: Longitudinal records of 30 untreated white subjects (13 girls, 17 boys) with skeletal Class II malocclusion were collected at ages 9, 12, 14, and 16 years. They had participated in the Burlington Growth Centre study, and cephalograms were analyzed with Dentofacial Planner Plus software (version 2.0, Dentofacial Planner, Toronto, Ontario, Canada). Serial means were compared with the Bonferroni post-hoc test (P <0.05). Predictive equations were obtained and studied with the analysis of agreement. RESULTS: Gradually, means of MPAH had statistical increments with sexual dimorphism from 14 to 16 years of age. A distal mean of AIMFM was found at 9 years of age that decreased significantly during growth, with sexual dimorphism between the ages of 9 and 12 years. Changes in AIMFM varied among subjects in distinct stages. Values of MPAH were predicted with high validity at intervals of 3 years or longer, whereas estimations for AIMFM were unreliable. CONCLUSIONS: In this study group, there was significant alveolar growth, with a natural tendency to upright the distal inclination at the maxillary first molars.

Display of the incisors as functions of age and gender.

BACKGROUND: Older subjects usually show less of their upper incisors and more of their lower incisors than younger subjects. OBJECTIVES: To determine how much of the upper and lower central incisor crowns are visible in Brazilian subjects with their lips at rest. METHODS: The subjects were 240 white Brazilian subjects divided into four age groups: Group 1, 12 to 15 years of age; Group 2, 20 to 30 years of age; Group 3, 31 to 50 years of age and Group 4, 51 years of age and older. Each group contained 30 males and 30 females. The vertical display of the incisors was measured in millimetres from the midpoints of the incisal edges of the upper and lower central incisors to the borders of the upper and lower lips. RESULTS: In females, the mean upper central incisor display reduced from 4.45 mm in Group 1 to 1.32 mm in Group 4, and in males it reduced from 3.35 mm in Group 1 to 0.57 mm in Group 4. Less of the lower central incisor crowns were displayed in Group 1 females (Mean: 0.47 mm) than in Group 4 females (Mean: 2.22 mm), and in Group 1 males (Mean: 0.61 mm) than in Group 4 males (Mean: 3.05 mm). Brazilian women showed significantly more of their upper incisor crowns than Brazilian men in Groups 1, 2 and 4, whereas Brazilian men showed significantly more of their lower central incisors than Brazilian women in Group 4. CONCLUSIONS: With the lips at rest, older Brazilians display less of their upper central incisors and more of their lower central incisors than young Brazilians. Women show more of their upper incisors than men, while men display more of their lower central incisors than women.

Global gene expression profile of periodontal ligament cells submitted to mechanical loading: A systematic review.

OBJECTIVE: To evaluate the evidence reporting gene expression array data of human in vitro cultured periodontal ligament cells (PDLCs) submitted to static mechanical loading compared to a control group. DESIGN: Systematic searches were performed in MEDLINE/PubMed, Scopus, Web of Science, Virtual Health Library, The Cochrane Library and the System for Information on Grey Literature in Europe up to June 2019. A narrative synthesis was performed to summarize differentially expressed genes (DEGs). These were grouped according to the culture method (2D or 3D), force type (compression or tension) and observation time. Additionally, gene ontology (GO) analysis was performed using the Database for Annotation Visualization and Integrated Discovery. The risk of bias (RoB) and certainty of evidence (CoE) were assessed using a modified CONSORT checklist and the GRADE tool, respectively. RESULTS: Of eight studies included (all rated as having moderate RoB), only two provided the complete list of DEGs and four studies performed GO, gene network or pathways analysis. "Cell proliferation", "cell-cell signaling", "response to hypoxia and to mechanical stimulus" were among the significantly enriched biological processes in 3D-cultured compressed PDLCs (moderate CoE); while "collagen catabolic process", "extracellular matrix organization" and "cell proliferation" were associated with DEGs of 3D-cultured PDLCs submitted to tension (very low CoE). Biological processes significantly enriched in 2D-cultured PDLCs under compression were "extracellular matrix organization", "canonical glycolysis" and "glycolytic process" (very low CoE). CONCLUSION: Genes such as NR4A2, NR4A3, NAMPT, PGK1, and REDD1 are suggested as novel biomarkers for orthodontic tooth movement. Limited amount of evidence on the complete gene expression profile and the high heterogeneity in methodologies make it impossible to obtain definite conclusions. New studies following standardized and well-designed in vitro model and reporting complete gene expression datasets are needed.

Rates of tooth movement and bone remodeling activity: Self-ligating versus conventional brackets.

BACKGROUND: Bracket systems have been developed with the purpose of reducing frictional resistance between the archwire and accessories. The aim of this research was to compare rates of tooth movement and regions of cellular bone modeling activity along tooth root surfaces of teeth moved with conventional vs. self-ligating brackets. MATERIAL AND METHODS: The experiments were conducted in 20 male dogs. Bands were cemented in all intermediate incisors, with conventional brackets (Morelli) on the right side and hybrid self-ligating ones (T3-American Orthodontics) on the left side. A 0.019" x 0.025" stainless steel wire was inserted passively in the slot of these brackets with chain elastics (250 gf) to perform sliding mechanics. Clinical records of the orthodontic mechanics were made before and after 15 days of the tooth movement. The dental segments of the animals were prepared for light microscopy. Statistical analysis of variance and the Tukey correction with a P value at 5% were used. RESULTS: There were no significant differences in tooth movement rates between the two types of brackets but differences, in the bone modeling activity, suggested that tooth movement with the self-ligating brackets resulted in more tipping and less translational movement than tooth movement with the conventional brackets. CONCLUSIONS: The rates of tooth movement were similar between the two systems. The histological evaluation of cellular bone modeling activity along tooth root surfaces showed more translation movement of teeth with the conventional brackets, and more tipping movement of teeth with self-ligating brackets. Key words:Edgewise, histological reactions, orthodontic movement, self-ligating, brackets.

In vitro antioxidant potential of medicinal plant extracts and their activities against oral bacteria based on Brazilian folk medicine.

BACKGROUND AND OBJECTIVES: This study aims to determine antibacterial activities of Cocos nucifera (husk fiber), Ziziphus joazeiro (inner bark), Caesalpinia pyramidalis (leaves), aqueous extracts and Aristolochia cymbifera (rhizomes) alcoholic extract against Prevotella intermedia, Porphyromonas gingivalis, Fusobacterium nucleatum, Streptococcus mutans and Lactobacillus casei. The antioxidant activity and acute toxicity of these extracts were also evaluated. MATERIAL AND METHODS: The plant extracts antibacterial activity was evaluated in vitro and the minimal inhibitory concentration (MIC) was determined by the broth micro-dilution assay. The bacterial killing kinetic was also evaluated for all extracts. In addition, the antibacterial effect of the extracts was tested in vitro on artificial oral biofilms. The acute toxicity of each extract was determined in according to Lorke [Lorke D. A new approach to practical acute toxicity testing. Arch Toxicol 1983;54:275-87] and the antioxidant activity was evaluated by DPPH photometric assay [Mensor LL, Menezes FS, Leitão GG, Reis AS, Santos TC, Coube CS, et al. Screening of Brazilian plants extract for antioxidant activity by the use of DPPH free radical method. Phytother Res 2001;15:127-30]. RESULTS: MIC and the bactericidal concentrations were identical, for each evaluated extract. However, microbes of artificial biofilms were less sensitive to the extracts than the planktonic strains. A. cymbifera extract induced the highest bactericidal effect against all tested bacteria, followed by C. nucifera, Z. joazeiro and C. pyramidalis extracts, respectively. All extracts showed good antioxidant potential, being C. nucifera and C. pyramidalis aqueous extracts the most active ones. CONCLUSION: In conclusion, all oral bacteria tested (planktonic or in artificial biofilms) were more susceptible to, and rapidly killed in presence of A. cymbifera, C. pyramidalis and C. nucifera than Z. joazeiro extracts, respectively. Thus, these extracts may be of great interest for future studies about treatment of oral diseases, considering their potent antioxidant activity and low toxicity.

Effect of crown fracture on the surrounding periodontium.

Clinical and histological alterations were analyzed in the periodontium of dog's teeth that had been submitted to crown fracture. To reach the long axis of the tooth, an impact device was applied to eight teeth of four adult dogs to produce trauma. Crown fractures involving the enamel and dentin, with or without pulpar exposure and without dislocation, mobility or gingival bleeding were analyzed within the post-trauma periods of 30 min, 1, 3, and 7 days. The force of impact that resulted in coronary fracture, although dissipated at the time of fracture, reverberated in the surrounding periodontium and may generate not only light histological alterations with a rapid re-establishment of the tissues, but also an intense inflammatory condition required as long as 7 days to clear up. The gravity of these inflammatory reactions unleashed in these teeth's periapical tissues depends on the absorption of impact by the periodontal structures and the individual susceptibility of each organism.

Clinical and histological alterations in the surrounding periodontium of dog's teeth submitted for an intrusive luxation.

The clinical and histological alterations on periodontium of dog's teeth after an intrusion luxation was analyzed. An impact device was used on 12 teeth of six adult dogs with the purpose of making a dislocation on the long axis of these teeth. Of the teeth that suffer intrusion luxation, two did not receive treatment and ten were replaced by orthodontic extrusion with activated springs of 100 gf. The traction was initiated either immediately after the trauma or 7 days later. Observation time was 40 days. Endodontic therapy with calcium hydroxide was performed on the fourteenth day after the intrusive luxation. The intruded teeth that did not receive appropriate treatment had signs of extensive and progressive inflammatory resorption. The teeth that were moved immediately after the trauma had lesser degree of replacement resorption compared with those that were extruded 7 days after the trauma.

Class II Division 1 malocclusion with severe overbite: cephalometric evaluation of the effects of orthodontic treatment.

AIM: To evaluate the effects of orthodontic treatment among individuals with Class II Division 1 malocclusion and severe overbite. METHODS: The sample was made up of 70 patients (35 males and 35 females), with an average age of 11.6 years in pretreatment and 14.9 years in posttreatment. One hundred forty lateral cephalograms were obtained and traced by a single investigator. All individuals were treated with the edgewise technique associated with the Kloehn cervical extraoral headgear during the growth spurt, and simultaneously presented ANB > or = 5 degrees and overbite > or = 4 mm. Statistical analysis involved t tests for both independent and paired samples and the Spearman correlation test. RESULTS: There were no significant differences between genders regarding the effects of treatment. The cases treated with extraction presented a greater reduction in the SNA angle. On average, all the variables of the study were significantly different when comparing the pretreatment and posttreatment conditions, except for the measurement of the mandibular plane angle (SNGoMe). CONCLUSION: Correction of severe overbite occurred in virtue of the intrusion of the maxillary and mandibular incisors associated to a reduction of the maxillary prognathism and differential growth of the mandible, as well as dentoalveolar growth.

Relação entre desmame precoce, desenvolvimento de hábitos bucais deletérios e maloclusões na infância / Relationship between early weaning, development of harmful oral habits and malocclusions in childhood

Objetivo: o objetivo desta pesquisa foi analisar a associação do tempo de aleitamento materno com a prática de hábitos deletérios e o desenvolvimento de maloclusões na primeira infância. Materiais e Métodos: foram aplicados 171 formulários às mães com 18 anos ou mais que acompanharam o processo de amamentação de seu(s) filho(s) de 4 a 10 anos de idade. O questionário foi composto por 22 perguntas, sendo 15 específicas e relacionadas ao aleitamento, hábitos deletérios da criança (uso de chupeta, sucção de dedo e sucção do próprio lábio) e maloclusões específicas (mordida cruzada posterior, mordida cruzada anterior e mordida aberta). Resultados: a prevalência da amamentação exclusiva por 6 meses ou mais foi de 52%, enquanto 29,8% das crianças foram amamentadas de 0 a 5 meses e 18,2% nunca foram amamentadas no seio exclusivamente. Quanto a alimentação complementar, grande parcela (37,4%) encontrada evidenciou início após os 6 meses; 57,9% das mães relataram algum tipo de dificuldade para amamentar e 34,5% das crianças fizeram uso de chupeta. Em relação aos hábitos deletérios, 10% desenvolveram sucção de dedo. O relato de desenvolvimento de maloclusões foi de 9,4% das crianças com mordida cruzada posterior; 7,6% mordida cruzada anterior e 18,7% mordida aberta anterior. Conclusão: sendo assim, é possível inferir que o tempo preconizado pela Organização Mundial da Saúde para aleitamento materno exclusivo foi fundamental para o não desenvolvimento de hábitos deletérios e maloclusões. Em contrapartida, quanto mais cedo a introdução de alimentos complementares, e a interrupção do aleitamento exclusivo nos seis primeiros meses, maior o risco do desenvolvimento de hábitos e consequentemente maloclusões.

Objective: the objective of this research was to analyze the association of breastfeeding duration with the practice of deleterious habits and the development of malocclusions in early childhood. Materials and Methods: a total of 171 forms were applied to mothers aged 18 years or older who followed the breastfeeding process of their child(ren) between 4 and 10 years of age. The questionnaire consisted of 22 questions, 15 of which were specific and related to breastfeeding, the child's deleterious habits (use of a pacifier, finger sucking and lip sucking) and specific malocclusions (posterior crossbite, anterior crossbite and open bite). Results: the prevalence of exclusive breastfeeding for 6 months or more was 52%, while 29.8% of children were breastfed from 0 to 5 months and 18.2% were never exclusively breastfed. As for complementary feeding, a large portion (37.4%) found to start after 6 months; 57.9% of the mothers reported some type of difficulty in breastfeeding and 34.5% of the children used a pacifier. Regarding deleterious habits, 10% developed finger sucking. The report of development of malocclusions was 9.4% of children with posterior crossbite; 7.6% anterior crossbite and 18.7% anterior open bite. Conclusion: therefore, it is possible to infer that the time recommended by the World Health Organization for exclusive breastfeeding was fundamental for the non-development of deleterious habits and malocclusions. On the other hand, the earlier the introduction of complementary foods and the interruption of exclusive breastfeeding in the first six months, the greater the risk of developing habits and, consequently, malocclusions.

Urinary excretion levels of nickel in orthodontic patients.

INTRODUCTION: Nickel, a primary component of orthodontic appliances, causes more allergic reactions than all other metals combined and can initiate a wide range of hypersensitivity reactions in susceptible subjects. The purpose of this study was to compare pretreatment and treatment levels of nickel in the urine of orthodontic patients wearing fixed appliances. METHODS: Urine specimens were collected from 21 orthodontic patients (12 female, 9 male) before placement of orthodontic appliances and 2 months after placement. Nickel ion analysis was carried out with atomic absorption spectrophotometry. The results were submitted to descriptive analyses, the Student t test, and ANOVA for repeated measurements (P <.05). RESULTS AND CONCLUSIONS: Urinary nickel levels increased significantly 2 months after the placement of orthodontic appliances. The results were similar in both sexes. Continued follow-up is needed to determine the patterns and the long-term significance of nickel release.

Soft-tissue changes during facial growth in skeletal Class II individuals.

INTRODUCTION: In orthodontic treatment, a harmonious soft-tissue profile can be difficult to achieve; the thickness of the soft tissues can vary greatly, and changes with growth and treatment can be difficult to predict. The purpose of this study was to investigate changes in the thickness and the length of the soft tissues of the nose, upper and lower lips, and chin due to growth from 6 to 16 years of age. METHODS: Cephalograms of 36 subjects (22 boys, 15 girls) with skeletal Class II malocclusions were analyzed. They participated in the Burlington Growth Study, and longitudinal records had been collected at ages 6, 9, 12, 14, and 16 years. The cephalograms were digitized and analyzed with Dentofacial Planner Plus (version 2.0; Dentofacial Software, Toronto, Ontario, Canada) software. Statistical analysis was performed with the nonparametric Friedman test, and comparisons among means were made with 1-way ANOVA software. RESULTS: All structures showed some growth at all stages. The nose showed the greatest increases in thickness and length in both sexes. There was sexual dimorphism at 16 years, with higher values for boys. Upper lips tended to reduce in the girls. Upper lip length showed slight increases, and base of the upper lip showed small increases for both sexes. The lower lip had moderate increases in all measurements, and its thickness showed sexual dimorphism at almost all ages. The soft tissues of the chin increased in both thickness and length, with no sexual dimorphism.

Human dental follicle cells express embryonic, mesenchymal and neural stem cells markers.

OBJECTIVE: This study was conducted to identify and characterize dental follicle stem cells (DFSCs) by analyzing expression of embryonic, mesenchymal and neural stem cells surface markers. Design Dental follicle cells (DFCs) were evaluated by immunocytochemistry using embryonic stem cells markers (OCT4 and SOX2), mesenchmal stem cells (MSCs) markers (Notch1, active Notch1, STRO, CD44, HLA-ABC, CD90), neural stem cells markers (Nestin and ß-III-tubulin), neural crest stem cells (NCSCs) markers (p75 and HNK1) and a glial cells marker (GFAP). RT-PCR was performed to identify the expression of OCT4 and NANOG in DFCs and dental follicle tissue. RESULTS: Immunocytochemistry and RT-PCR analysis revealed that a significant proportion of the DFCs evaluated expressed human embryonic stem cells marker OCT4 (75%) whereas NANOG was weakly expressed. A considerable amount of MSCs (90%) expressed Notch1, STRO, CD44 and HLA-ABC. However, they were weakly positive for CD90. Moreover, it was possible to demonstrate that dental follicle contains a significant proportion of neural stem/progenitors cells, expressing ß-III-tubulin (90%) and nestin (70%). Interestingly, immunocytochemistry showed DFCs positive for p75 (50%), HNK1 (<10%) and a small proportion (<20%) of GFAP-positive cells. This is the first study reporting the presence of NCSCs and glial-like cells in the dental follicle. CONCLUSIONS: The results of the present study suggest the occurrence of heterogeneous populations of stem cells, particularly neural stem/progenitor cells, in the dental follicle, Therefore, the human dental follicle might be a promising source of adult stem cells for regenerative purposes.

Long-term clinical outcome of rapid maxillary expansion as the only treatment performed in Class I malocclusion.

The purpose of this study was to investigate the long-term clinical responses of rapid maxillary expansion as the only treatment performed in Class I malocclusion using the Haas-type appliance. The longitudinal sample consisted of 90 sets of study models from 30 consecutive patients (12 males and 18 females) selected on the basis of the following inclusion criteria: all patients (1) had a Class I malocclusion with transverse maxillary/mandibular skeletal discrepancies, (2) were treated nonextraction in the early/ mid mixed dentition, (3) presented with mandibular dental arches with mild or no crowding, and (4) had no subsequent comprehensive orthodontic treatment implemented in either the maxilla or the mandible. The mean age was 8.2 years when treatment was initiated. Treatment outcomes were evaluated at pretreatment A1, short-term follow-up (one year after A1) A2, and long-term follow-up (four years after A2) A3. The changes in maxillary arch width and arch length were quantified and compared among assessment stages A1, A2, and A3 using the Student's t-test. The results demonstrated a highly significant increase in maxillary arch width in both the short- and long-term follow-ups. The arch width increased significantly during treatment and decreased slightly during the long-term follow-up. The long-term clinical response demonstrated the efficacy and stability of this type of treatment in achieving maxillary arch width. The follow-up examination during the early/mid/permanent dentition confirmed the validity of overtreatment.