Effect of vitamin D on bone morphometry and stability of orthodontic tooth movement in rats.

INTRODUCTION: Vitamin D (VitD) maintains bone health and may influence orthodontic tooth movement (OTM). The objective was to evaluate the VitD effect on bone morphometry and the rate and stability of OTM. METHODS: Thirty-two male Sprague Dawley rats were assigned into 2 experimental groups, treated with VitD by gavage (systemic) or injection (local), and 2 respective control groups treated with phosphate-buffered saline for 47 days. OTM was performed for 7 days with a nickel-titanium coil bonded between the maxillary first molar and incisors. Microcomputed tomography scanning was performed at 5 time points: before administration of VitD, the start of OTM, the end of OTM, 7 days post-OTM, and 30 days post-OTM. The rate and stability of OTM were assessed. Bone morphometry was analyzed by bone mineral density, bone volume/total volume, total porosity, trabecular pattern factor, structure model index, and connectivity density. RESULTS: The systemic VitD group showed a lower OTM rate and a lower relapse than the control (P <0.05). It also demonstrated increased bone mineral density, bone volume/total volume, and a decrease in total porosity (P <0.05). The bone structure appeared more fragmented and presented a lower connectivity density than the control (P <0.05). No statistical difference was found between VitD local administration and the other groups for the rate and stability of OTM or bone morphometry. CONCLUSIONS: The systemic administration of VitD caused a decrease in the OTM rate by generating more bone resistance but also contributed to a lower relapse with a higher bone mineral density.

Impact of piezocision-assisted orthodontics on root resorption and alveolar bone: a prospective observational study.

OBJECTIVES: To assess the impact of orthodontic treatment combined with piezocision (OT-PC) on root structure and alveolar bone. MATERIALS AND METHODS: Twelve adults were treated with OT-PC. Pre- and post-treatment CBCT examinations evaluated apical root resorption (ARR) and alveolar bone height and thickness changes. Pre- and post-treatment differences were compared using one-sample t test and Wilcoxon signed-rank test. RESULTS: ARRs were generalized and significantly more severe in both anterior sextants compared with posterior sextants. Bone thickness decreased significantly in the maxilla at mid-root and apex areas. The majority of mandibular alveolar bone dehiscences occurred on the buccal aspect at the mid-root level, especially where thickness was less than 0.3 mm. Overall bone height decreased twice as much on the buccal aspect (1.43 mm, P < 0.001) compared with the lingual aspect (0.67 mm, P = 0.001), most significantly in the lower incisors, where the average median loss was 2.10 mm (P = 0.003). CONCLUSION: OT-PC causes minor negative effects on both alveolar bone and root resorption. CLINICAL RELEVANCE: Orthodontic treatment combined with piezocision causes minor negative effects on periodontal support. Nevertheless, mild bone height loss on the buccal aspect of the mandibular teeth and root resorption in both anterior sextants have been detected with this new treatment.

Dental malocclusion among children with attention deficit hyperactivity disorder.

INTRODUCTION: Children with attention deficit hyperactivity disorder (ADHD) have more sleep breathing problems and parafunctional oral habits than individuals without ADHD. However, there is scarce information on the correlation between their dental malocclusion and these functional disorders. The objective of this study was to assess the severity of malocclusion in patients with and without ADHD and to evaluate the correlation between their functional disorders and dental malocclusion. METHODS: Eighty-eight patients aged 6-17 years were divided into 2 groups: ADHD (n = 44) and control (n = 44). A medical questionnaire to assess functional disorders and an orthodontic examination to evaluate malocclusion were completed for each patient. Distribution of the data was evaluated using Shapiro-Wilk test, whereas the 2 groups were compared with a t test, Mann-Whitney U test, Fisher exact test, and Spearman correlation. The association between parafunctional oral habits, ADHD drug intake, and malocclusion severity were assessed with a t test and Mann-Whitney U test. RESULTS: Patients with ADHD had significantly higher severity of malocclusion (P = 0.042), more dental rotation (P = 0.021) and more parafunctional oral habits (P = 0.001), specifically bruxism (P = 0.005), and a history of pacifier use (P = 0.009), than the control group. CONCLUSIONS: It is important to be aware of the increased risk of parafunctional oral habits and dental malocclusion among ADHD patients to develop preventive programs, as well as therapeutic strategies for them.

Piezocorticision-assisted orthodontics: Efficiency, safety, and long-term evaluation of the inflammatory process.

OBJECTIVES: The aim of this work was to compare the duration of treatment between orthodontic treatment combined with piezocorticision (OT-PC) and conventional orthodontic treatment (COT), as well as to evaluate the safety, inflammatory process, periodontal health, and soft tissue healing in the OT-PC group. METHODS: Twelve patients were included in each group, and their treatment times were compared for preliminary bracket alignment (PBA) and for overall treatment. In the OT-PC group, the inflammatory process was evaluated by quantifying cytokines in the gingival crevicular fluid. A calibrated examiner measured the probing depth (PD), the distance between the gingival margin and the cementoenamel junction (GM-CEJ), and the clinical attachment level (CAL), before and after OT-PC. The presence of gingival scars was evaluated. Bone and root injuries were assessed with the use of cone-beam computed tomography. RESULTS: The treatment time was significantly reduced in the OT-PC group for PBA in both maxilla (45%; P = 0.001) and mandible (31%; P = 0.023), as well as for overall treatment (52%; P < 0.0001). Although not statistically significant, several inflammatory mediators demonstrated peaks at 3-5 and 16 weeks. There were not significant changes in PD and GM-CEJ after OT-PC treatment, unlike CAL (0.09 ± 0.12 mm; P = 0.024); 47.5% of piezocorticisions caused gingival scars. Only one patient showed no scars. Four cortical bones did not heal completely, and 2 roots had piezoelectric injuries. CONCLUSION: OT-PC was effective at reducing the orthodontic treatment time.

Expression of odontogenic ameloblast-associated and amelotin proteins in the junctional epithelium.

Two novel proteins - odontogenic ameloblast-associated protein and amelotin - have recently been identified in maturation-stage ameloblasts and in the junctional epithelium. This article reviews the structure and function of the junctional epithelium, the pattern of expression of odontogenic ameloblast-associated and amelotin proteins and the potential involvement of these proteins in the formation and regeneration of the junctional epithelium.

Gene expression profiling and histomorphometric analyses of the early bone healing response around nanotextured implants.

UNLABELLED: While in vitro studies have shown that nanoscale surface modifications influence cell fate and activity, there is little information on how they modulate healing at the bone-implant interface. AIM: This study aims to investigate the effect of nanotopography at early time intervals when critical events for implant integration occur. MATERIALS & METHODS: Untreated and sulfuric acid/hydrogen peroxide-treated machined-surface titanium alloy implants were placed in rat tibiae. Samples were processed for DNA microarray analysis and histomorphometry. RESULTS: At both 3 and 5 days, the gene expression profile of the healing tissue around nanotextured implants differed from that around machined-surface implants or control empty holes, and were accompanied by an increase in bone-implant contact on day 5. While some standard pathways such as the immune response predominated, a number of unclassified genes were also implicated. CONCLUSION: Nanotexture elicits an initial gene response that is more complex than suspected so far and favors healing at the bone-implant interface.

Expression pattern of odontogenic ameloblast-associated and amelotin during formation and regeneration of the junctional epithelium.

The junctional epithelium (JE) adheres to the tooth surface, and seals off periodontal tissues from the oral environment. This incompletely differentiated epithelium is formed initially by the fusion of the reduced enamel organ with the oral epithelium (OE). Two proteins, odontogenic ameloblast-associated (ODAM) and amelotin (AMTN), have been identified in the JE. The objective of this study was to evaluate their expression pattern during formation and regeneration of the JE. Cytokeratin 14 was used as a differentiation marker for oral epithelial cells, and Ki67 for cell proliferation. Immunohistochemistry was carried out on erupting rat molars, and in regenerating JE following gingivectomy. In the reducing enamel organ and in established JE, ODAM and AMTN were present at the cell-tooth interface while only ODAM and CK14 were found throughout the JE. Both were also conspicuously present in cell clusters situated between the erupting tooth and OE. During JE regeneration, ODAM was detected first at the leading wound edge and then in the regenerating JE. Some cell clusters in the subjacent connective tissue were also positive for ODAM. AMTN appeared later and both AMTN and ODAM accumulated at the interface with the tooth. Cytokeratin 14 gradually appeared in the regenerating JE but the cell clusters showed variable labeling. Cells associated with JE formation and regeneration exhibited higher division activity than adjacent epithelial cells. These findings suggest that ODAM and AMTN have a role at the cell-tooth interface, and that ODAM is likely also implicated in cellular events during formation and regeneration of the JE.

Agreement evaluation of a newly proposed system for malocclusion classification / Acuerdo de evaluación de un sistema de nuevas propuestas de clasificación de la maloclusión

The current malocclusion classification systems, routinely used in orthodontic practice, still yield different disagreement values among examiners who evaluate one and the same clinical case. Objectives: The purpose of this study was to evaluate the agreement effectiveness of a Newly Proposed System for malocclusion classification – in the anteroposterior orientation -, conceived by the present authors. Thirty-four examiners evaluated 15 malocclusion cases using Angle's, Katz’sand the Newly Proposed System classifications to determine which system shows the highest degree of agreement and accuracy when results were communicated among examiners. A comparison of the classifications attributed to each individual case and the mean figures found for the total data in each classification showed that the methods advanced by the Newly Proposed System yielded a higher degree of agreement (73.33 percent) than Angle’s (26.66 percent) and Katz’s (26.66 percent). The Newly Proposed System proved to be an outstanding malocclusion classification system with a high degree of agreement among examiners. On the other hand, however, further studies involving a wider sample of malocclusions and a greater number of examiners are strongly recommended if more conclusive results are to be achieved.

Los sistemas actuales de clasificación de maloclusión, habitualmente utilizados en la práctica de ortodoncia, siendo los distintos valores un desacuerdo entre los examinadores que evalúan un caso clínico y o el mismo caso. El objetivo de este estudio fue evaluar la eficacia de un nuevo sistema propuesto para la clasificación de maloclusión - en la orientación anteroposterior -, concebida por los autores de este estudio. Treinta y cuatro examinadores evaluaron 15 casos de maloclusión utilizando las clasificaciones de Angle, Katz y el nuevo sistema propuesto de clasificación, para determinar cual de los sistemas muestran el mayor grado de acuerdo y precisión cuando los resultados fueron comunicados entre los examinadores. La comparación de las clasificaciones atribuidas a cada caso particular y las medias encontrada para los datos totales de cada clasificación mostró que los métodos avanzados del nuevo sistema propuesto dio un mayor grado de acuerdo (73,33 por ciento) que (Angle 26,66 por ciento) y Katz (26,66 por ciento). El nuevo sistema propuesto demostró ser un sistema de clasificación de la maloclusión con un alto grado de acuerdo entre los examinadores. Sin embargo, otros estudios con una muestra más amplia de maloclusiones y un mayor número de examinadores se recomienda para alcanzar resultados más concluyentes.

Evaluation of esthetic brackets' resistance to torsional forces from the archwire.

INTRODUCTION: The aim of this study was to evaluate the resistance to deformation or fracture of esthetic brackets produced by archwire torsion. METHODS: Six types of maxillary right central incisor brackets were analyzed: traditional ceramic brackets (cer); ceramic brackets reinforced with a stainless steel slot (cer/ss); ceramic brackets reinforced with a gold slot (cer/gold); traditional polycarbonate brackets (poly); polycarbonate brackets reinforced with a stainless steel slot (poly/ss); and polycarbonate brackets reinforced with ceramic fillers and a stainless steel slot (poly/cer/ss). Stainless steel wire segments were used, and the testing instrument (Emic DL 10000, São José do Rio Preto, PR, Brazil) was moved at a rate of 1 inch per minute to generate the wire torsion. RESULTS: The brackets showed deformation or fracture resistance values (gf x mm) in decreasing order as follows: cer/ss (3528.1 +/- 516.6), cer/gold (2858.7 +/- 611.6), cer (2424.0 +/- 352.1), poly/cer/ss (2279.5 +/- 174.5), poly/ss (2142.0 +/- 275.7), and poly (1463.6 +/- 193.3). The cer/ss ceramic brackets showed the greatest statistically significant (P <0.01) values of resistance to fracture, and the poly brackets had the lowest statistically significant (P <0.01) values of resistance to deformation. The cer brackets showed no significant differences (P >0.01) from the cer/gold, the poly/cer/ss, and the poly/ss brackets. CONCLUSIONS: This suggested that the stainless steel slot might enhance resistance to deformation or fracture, although gold slots and ceramic fillers are ineffective for reinforcing esthetic brackets.

The effect of mechanical loading on the metabolism of growth plate chondrocytes.

It is well known that mechanical loading influences the endochondral bone formation essential for the growth and development of longitudinal bones. The question was, however, asked whether the effect of mechanical loading on the chondrocyte metabolism is dependent on the loading frequency. This study was aimed at evaluating the effect of tensile loadings with various frequencies on the proliferation of growth plate chondrocytes and extracellular matrix synthesis. The chondrocytes obtained from rib growth plate cartilage of 4-week-old male Wistar strain rats were cultured by day 4 and day 11 and used as proliferating and matrix-forming chondrocytes, respectively. Intermittent tensile stresses with different frequencies were applied to each stage chondrocyte. DNA syntheses were examined by measuring the incorporation of [(3)H]thymidine into the cells. Furthermore, the rates of collagen and proteoglycan syntheses were determined by measuring the incorporation of [2,3-(3)H]proline and [(35)S]sulfate into the cells, respectively. At the proliferating stage, intermittent tensions with the frequencies of 30 cycles/min and 150 cycles/min significantly (p < 0.05) upregulated the syntheses of DNA, which indicates the promotion of chondrocyte proliferation. At the matrix-forming stage, collagen, and proteoglycan syntheses also enhanced with increase of the loading frequency. In particular, the intermittent tension with the frequencies of 30 cycles/min and 150 cycles/min increased significantly (p < 0.05 or p < 0.01) both the collagen and proteoglycan syntheses. These results suggest that the proliferation and differentiation of growth plate chondrocytes are regulated by the mechanical loading and that the chondrocyte metabolism enhanced with increase of loading frequency. These may give more insight into the possible mechanism leading to endochondral bone formation.

Skeletal anchorage for orthodontic correction of severe maxillary protrusion after previous orthodontic treatment.

The correction of a severe maxillary protrusion in an adult by distal movement of the maxillary molars has been one of the most difficult biomechanical problems in orthodontics. This article reports on the treatment of an adult case of severe maxillary protrusion and a large overjet treated with a skeletal anchorage system. A female patient, age 22 years and 3 months, complained of the difficulty of lip closure due to severe maxillary protrusion with a gummy smile. Overjet and overbite were +7.6 mm and -0.9 mm, respectively. She had a history of orthodontic treatment in which her maxillary first premolars were extracted. In order to conduct distal movement of the maxillary molars, anchor plates were placed in the zygomatic process. After achieving a Class I molar relationship, retraction and intrusion of the maxillary incisors were performed. After a 2-year treatment, an acceptable occlusion was achieved with a Class I molar relationship. Her convex facial profile with upper lip protrusion was considerably improved, and the lips showed less tension in lip closure. After a 2-year retention period, an acceptable occlusion was maintained without recurrence of maxillary protrusion, indicating a stability of the occlusion. The result of this treatment indicated that skeletal anchorage is of great importance as a remedy for achieving intrusion and retraction of the maxillary incisors in cases of severe maxillary protrusion with a patient who had previous orthodontic treatment.

Avaliação do metabolismo celular decorrente da aplicação de força nos condrócitos do côndilo mandibular e do joelho de suínos / Comparison of in vitro desponse to mechanical loading between the porcine mandibular condyle and ankle articular cartilages

Funcionalmente, a cartilagem da articulação têmporo-mandibular assemelha-se à cartilagem da articulação do joelho por possuírem lubrificação para resistir à fricção e fornecerem proteção às forças mecânicas externas. Entretanto, o efeito das forças de tensão sobre as cartilagens dessas duas articulações ainda permanece obscura. O objetivo desse estudo foi avaliar, in vitro, as alterações metabólicas nos condrócitos extraídos do tecido cartilaginoso do côndilo mandibular e do joelho de suínos, decorrentes da aplicação de forças mecânicas, em relação à síntese de DNA e de proteoglicanos (PTG). Além disso, foi verificada a expressão de colágeno tipo II e de agrecanos no RNAm dos condrócitos dessas duas articulações, tempo-dependente do cultivo celular, utilizando-se a análise quantitativa de PCR em tempo real. Os condrócitos foram submetidos às forças mecânicas de tração de 2 kPa (3 porcento de alongamento), 5 kPa (7 porcento de alongamento) e 10 kPa (12 porcento de alongamento), em uma freqüência de 30 ciclos/min. durante 12 e 24 horas. Os resultados demonstraram que os condrócitos do côndilo mandibular quando submetidos às forças de 2 kPa e de 5 kPa, apresentaram um aumento estatisticamente significativo da síntese de DNA e de PTG, em 12 h. (p < 0,01) e em 24 h. (p < 0,05). Exceto o aumento da síntese de DNA do grupo submetido à força de 5 kPa que durante 24h. não foi estatisticamente significativo (p > 0,05). A força de 10 kPa causou uma diminuição estatisticamente significativa na síntese de DNA e de PTG nos condrócitos do côndilo mandibular, em ambos os tempos de ensaio mecânico (p < 0,01). Por outro lado, os condrócitos do joelho apresentaram um aumento na síntese de DNA e de PTG quando submetidos à todas as magnitudes de força de tração...

Functionally, the mandibular condylar cartilage is similar to the ankle articular cartilage, both provides lubrication to resist friction and offers protection against external mechanical loading. However, the effect of tension loadings on these two articular cartilages remains unclear. The purpose of this study was to evaluate in vitro, the metabolism of the chondrocytes isolated from the cartilage tissues of porcine mandibular condyle and ankle, in response to the tension mechanical forces, related to the syntheses of DNA and proteoglycan (PTG). It was also verified the expression of mRNA type II collagen and aggrecan on the condrocytes of these two joints on culture time-dependent, using a quantitative real-time PCR analysis. The chondrocytes were submitted to tensile mechanical strains of 2 kPa (3 percent elongation), 5 kPa (7 percent elongation) and 10 kPa (12 percent elongation), with a frequency of 30 cycles/min for 12 and 24 hours. The results showed that the condrocytes from mandibular condyle, when submitted to tension forces of 2 kPa and 5 kPa, demonstrated a statistically significant enhancement of DNA and PTG, in 12 h. (p < 0.01) and in 24 h. (p < 0.05). Except the increase of DNA synthesis of the group submitted to the force of 5 kPa during 24 h. that was not statistically significant (p > 0.05). The force of 10 kPa caused a statistically significant decrease of DNA and PTG syntheses on the condrocytes of mandibular condyle, in both periods of mechanical stimulation (p < 0.01). On the other side, the condrocytes of ankle showed an increase of DNA and PTG syntheses when subjected to all the magnitudes of tension forces...

Relationship between dental size and normal occlusion in Brazilian patients.

The present study was performed on dental casts and lateral cephalometric films of 30 Caucasian Brazilian individuals (15 males and 15 females) aged 18 to 27 years and 4 months, all presenting normal occlusion and satisfactory facial profile. The aims were to investigate the existence of dental discrepancies according to Bolton's criteria, to obtain mean values for overbite, overjet, curve of Spee and interincisal angle, and to demonstrate any correlation among these parameters. A single calibrated operator measured each variable characteristics and the process was recorded twice with an accurate modified digital caliper. It was observed that the sample of normal occlusion did not present any dental discrepancy among the 12 teeth of opposite arches. The overall ratio (91.46) and anterior ratio (77.83) were in accordance with those proposed by Bolton. The mean values for normal occlusion in this Brazilian sample were defined as: 2.45 mm for overbite; 1.92 mm for overjet; 1.01 mm for curve of Spee and 129.57 degrees for interincisal angle. A statistically significant correlation was found between overjet and overbite.

Relationship between dental size and normal occlusion in Brazilian patients

The present study was performed on dental casts and lateral cephalometric films of 30 Caucasian Brazilian individuals (15 males and 15 females) aged 18 to 27 years and 4 months, all presenting normal occlusion and satisfactory facial profile. The aims were to investigate the existence of dental discrepancies according to Bolton's criteria, to obtain mean values for overbite, overjet, curve of Spee and interincisal angle, and to demonstrate any correlation among these parameters. A single calibrated operator measured each variable characteristics and the process was recorded twice with an accurate modified digital caliper. It was observed that the sample of normal occlusion did not present any dental discrepancy among the 12 teeth of opposite arches. The overall ratio (91.46) and anterior ratio (77.83) were in accordance with those proposed by Bolton. The mean values for normal occlusion in this Brazilian sample were defined as: 2.45 mm for overbite; 1.92 mm for overjet; 1.01 mm for curve of Spee and 129.57° for interincisal angle. A statistically significant correlation was found between overjet and overbite.

O presente estudo foi realizado em modelos de gesso e radiografias cefalométricas laterais de 30 indivíduos brasileiros, leucodermas, sendo 15 do sexo feminino e 15 do sexo masculino, com idades variando de 18 anos a 27 anos e 4 meses, todos portadores de oclusão excelente e bom perfil facial. Os objetivos foram verificar a existência de discrepância dentária de Bolton, obter valores médios para a sobremordida (overbite), sobressaliência (overjet), curva de Spee e ângulo interincisivo e verificar a existência de correlação entre essas variáveis. As medições foram realizadas por um único avaliador e o procedimento realizado duas vezes com auxílio de um paquímetro digital modificado de alta precisão. Observou-se que a amostra de oclusão normal não apresentou discrepância dentária entre os doze dentes dos arcos opostos e as razões total (91,46) e anterior (77,83) foram próximos aos dos propostos por Bolton. Os valores médios encontrados como padrão para a amostra de oclusão normal de indivíduos brasileiros foram determinados em: 2,45 mm para a sobremordida; 1,92 mm para a sobressaliência; 1,01 mm para a curva de Spee e 129,57(0) para o ângulo interincisivo, havendo apenas correlação significativa entre sobressaliência e as classes de sobremordida.

In vitro evaluation of frictional forces between archwires and ceramic brackets.

The aim of this study was to evaluate the frictional force between orthodontic brackets and archwires. The differences in magnitude of the frictional forces generated by ceramic brackets, ceramic brackets with metal reinforced slot, and stainless steel brackets in combination with stainless steel, nickel-titanium, and beta-titanium orthodontic archwires were investigated. Brackets and wire were tested with tip angulations of 0 degrees and 10 degrees. Friction testing was done with the Emic DL 10000 testing machine (São José do Rio Preto, PR, Brazil), and the wires were pulled from the slot brackets with a speed of 0.5 cm/min for 2 minutes. The ligation force between the bracket and the wire was 200 g. According to the data obtained, the brackets had frictional force values that were statistically significant in this progressive order: stainless steel bracket, ceramic bracket with a metal reinforced slot, and traditional ceramic bracket with a ceramic slot. The beta-titanium wire showed the highest statistically significant frictional force value, followed by the nickel-titanium and the stainless steel archwires, in decreasing order. The frictional force values were directly proportional to the angulation increase between the bracket and the wire.

Cúspide em garra e dens in dente em um incisivo lateral girovertido: tratamento ortodôntico / Talon cusp and dens in dente in a torsioversion lateral incisor: orthodontic treatment

Os autores relatam um caso de giroversäo em um incisivo lateral com cúspide em garra e dens in dente, bem como seu tratamento ortodôntico