Prevalence of dentin hypersensitivity after orthodontic treatment: A cross-sectional study.

INTRODUCTION: The prevalence of cervical dentin hypersensitivity in patients after corrective orthodontic treatment has been poorly studied, although such hypersensitivity is very common. This study aimed to assess the prevalence of dentin hypersensitivity in patients who received corrective orthodontic treatment, the impact of general oral problems on quality of life, and the impact of hypersensitivity on the quality of life of this population. METHODS: This observational, cross-sectional study evaluated 232 patients who finished orthodontic treatment between 2000 and 2020 for self-reported hypersensitivity and clinically diagnosed hypersensitivity. The following tests were used: tactile, evaporative (bellows), evaporative (triple syringe), and thermal. The patients were also evaluated regarding their quality of life using questionnaires (Oral Health Impact Profile-14 and Dentine Hypersensitivity Experience Questionnaire). We evaluated data with nonparametric statistics. RESULTS: The prevalence of hypersensitivity was higher in women and in those aged <30 years; the most affected teeth were the mandibular incisors and premolars; different diagnostic tests for hypersensitivity may indicate different prevalence values; patients with hypersensitivity had a lower quality of life in most of the domains of both of the tests that were used. CONCLUSIONS: The prevalence of hypersensitivity among patients after orthodontic treatment may be higher than in the general population. Further investigation is needed to indicate the possible factors associated with orthodontic tooth movement.

Influence of radiant exposure values from two third generation LED curing units on polymerization profile and microhardness of orthodontic composite under ceramic and metallic brackets.

INTRODUCTION: Third generation of LED light curing units might be used in short exposure periods for orthodontic brackets bonding. OBJECTIVE: This study evaluated the effect of the different radiant exposure (RE) values: Manufacturers' instructions (MI), ½ MI, 1/4 MI and Turbo mode. Two third-generation LED curing units were used: VALO® and Bluephase 20i® . The degree of conversion (DC) and Vickers hardness (VHN) of an orthodontic composite (OC) (Transbond XT) under metallic (MB) or ceramic brackets (CB) were measured. METHODS: OC was applied to the bracket base, which was then placed over an attenuated total reflectance (ATR) table coupled to an infrared light spectroscope, or to a glass surface for the VHN analysis. The specimens were light-cured and DC values were calculated. The VHN was obtained in a microhardness tester. The data were analyzed with 2-way ANOVA followed by Tukey's post-hoc test (pre-set α=0.05). Linear regression analysis evaluated the relationship between RE values and dependent variables. RESULTS: CB allowed higher DC and VHN values than MB (p< 0.001). No significant difference was noted among groups when CB were used. For MB, MI groups showed the highest DC and VHN values. A significant, but weak relationship was found between delivered RE values and dependent variables. CONCLUSIONS: The decrease in RE values from third generation LED CU did not jeopardize the DC values when CB were used, but can compromise DC and VHN values when MB are used.

In vivo temperature rise and acute inflammatory response in anesthetized human pulp tissue of premolars having Class V preparations after exposure to Polywave® LED light curing units.

OBJECTIVE: To evaluate the influence of light emitted from two Polywave®, LED light-curing units (LCU) on in vivo pulp temperature (PT) rise and signs of acute inflammatory response in pulps of human premolar having deep Class V preparations. METHODS: Sixty intact, first premolars from 15 volunteers requiring extraction received infiltrative anesthesia. A sterile thermocouple probe was inserted within the pulp tissue through a minute occlusal pulp exposure in only 45 teeth (n = 9) to continuously monitor PT (°C). A deep buccal Class V preparation was created, and the surface was exposed to light from a commercial Polywave LCU (Bluephase 20i (20i), Ivoclar Vivadent) or from an experimental LCU (Exp) using the exposure modes (EM): 1s/Exp and 2s/Exp, 10s/20i, 20s/20i, and 60s/20i. Peak PT and PT rise values above baseline (ΔT) data were evaluated using a one-way ANOVA followed by Tukey's post-hoc test (α = 5%). Teeth used for histological and immunohistochemical analyses (n = 3) were extracted approximately 2 h after exposure to the LCU. RESULTS: No significant difference in peak PT and ΔT values was noted between 2s/Exp and 20s/20i groups, which both exhibited higher values than 1s/Exp and 10s/20i groups (p < 0.001). Dilated and congested blood vessels were seen after exposure to 1s/Exp, 2s/Exp, or 60s/20i EMs. The expression of IL-1ß and TNF-α tended to be more intense when higher irradiance was delivered. SIGNIFICANCE: Although higher irradiance delivered over a short exposure caused lower PT rise than 5.5 °C, such EMs should be used with caution, as they have more potential to harm the pulp tissue.

Comparison of in vivo and in vitro models to evaluate pulp temperature rise during exposure to a Polywave® LED light curing unit.

OBJECTIVES: To measure and compare in vivo and in vitro pulp temperature (PT) increase (ΔTEMP) over baseline, physiologic temperature using the same intact upper premolars exposed to the same Polywave® LED curing light. METHODOLOGY: After local Ethics Committee approval (#255,945), local anesthesia, rubber dam isolation, small occlusal preparations/minute pulp exposure (n=15) were performed in teeth requiring extraction for orthodontic reasons. A sterile probe of a temperature measurement system (Temperature Data Acquisition, Physitemp) was placed within the pulp chamber and the buccal surface was sequentially exposed to a LED LCU (Bluephase 20i, Ivoclar Vivadent) using the following exposure modes: 10-s low or high, 5-s Turbo, and 60-s high. Afterwards, the teeth were extracted and K-type thermocouples were placed within the pulp chamber through the original access. The teeth were attached to an assembly simulating the in vivo environment, being similarly exposed while real-time temperature (°C) was recorded. ΔTEMP values and time for temperature to reach maximum (ΔTIME) were subjected to two-way ANOVA and Bonferroni's post-hoc tests (pre-set alpha 0.05). RESULTS: Higher ΔTEMP was observed in vitro than in vivo. No significant difference in ΔTIME was observed between test conditions. A significant, positive relationship was observed between radiant exposure and ΔTEMP for both conditions (in vivo: r2=0.917; p<0.001; in vitro: r2=0.919; p<0.001). CONCLUSION: Although the in vitro model overestimated in vivo PT increase, in vitro PT rise was close to in vivo values for clinically relevant exposure modes.

Differential expression of osteoblast and osteoclast chemmoatractants in compression and tension sides during orthodontic movement.

Orthodontic tooth movement is achieved by the remodeling of alveolar bone in response to mechanical loading, and is supposed to be mediated by several host mediators, such as chemokines. In this study we investigated the pattern of mRNAs expression encoding for osteoblast and osteoclast related chemokines, and further correlated them with the profile of bone remodeling markers in palatal and buccal sides of tooth under orthodontic force, where tensile (T) and compressive (C) forces, respectively, predominate. Real-time PCR was performed with periodontal ligament mRNA from samples of T and C sides of human teeth submitted to rapid maxillary expansion, while periodontal ligament of normal teeth were used as controls. Results showed that both T and C sides exhibited significant higher expression of all targets when compared to controls. Comparing C and T sides, C side exhibited higher expression of MCP-1/CCL2, MIP-1alpha/CCL3 and RANKL, while T side presented higher expression of OCN. The expression of RANTES/CCL5 and SDF-1/CXCL12 was similar in C and T sides. Our data demonstrate a differential expression of chemokines in compressed and stretched PDL during orthodontic tooth movement, suggesting that chemokines pattern may contribute to the differential bone remodeling in response to orthodontic force through the establishment of distinct microenvironments in compression and tension sides.

Influence of Class V preparation on in vivo temperature rise in anesthetized human pulp during exposure to a Polywave® LED light curing unit.

OBJECTIVE: This in vivo study evaluated pulp temperature (PT) rise in human premolars having deep Class V preparations during exposure to a light curing unit (LCU) using selected exposure modes (EMs). METHODS: After local Ethics Committee approval, intact first premolars (n=8) requiring extraction for orthodontic reasons, from 8 volunteers, received infiltrative and intraligamental anesthesia and were isolated using rubber dam. A minute pulp exposure was attained and sterile probe from a wireless, NIST-traceable, temperature acquisition system was inserted into the coronal pulp chamber to continuously monitor PT (°C). A deep buccal Class V preparation was prepared using a high speed diamond bur under air-water spray cooling. The surface was exposed to a Polywave® LED LCU (Bluephase 20i, Ivoclar Vivadent) using selected EMs, allowing 7-min span between each exposure: 10-s in low (10-s/L), 10-s (10-s/H), 30-s (30-s/H), or 60-s (60-s/H) in high mode; and 5-s-Turbo (5-s/T). Peak PT values and PT increases over physiologic baseline levels (ΔT) were subjected to 1-way, repeated measures ANOVAs, and Bonferroni's post-hoc tests (α=0.05). Linear regression analysis was performed to establish the relationship between applied radiant exposure and ΔT. RESULTS: All EMs produced higher peak PT than the baseline temperature (p<0.001). Only 60-s/H mode generated an average ΔT of 5.5°C (p<0.001). A significant, positive relationship was noted between applied radiant exposure and ΔT (r2=0.8962; p<0.001). SIGNIFICANCE: In vivo exposure of deep Class V preparation to Polywave® LED LCU increases PT to values considered safe for the pulp, for most EMs. Only the longest evaluated EM caused higher PT increase than the critical ΔT, thought to be associated with pulpal necrosis.

A posteriori registration and subtraction of periapical radiographs for the evaluation of external apical root resorption after orthodontic treatment.

PURPOSE: This study employed a posteriori registration and subtraction of radiographic images to quantify the apical root resorption in maxillary permanent central incisors after orthodontic treatment, and assessed whether the external apical root resorption (EARR) was related to a range of parameters involved in the treatment. MATERIALS AND METHODS: A sample of 79 patients (mean age, 13.5±2.2 years) with no history of trauma or endodontic treatment of the maxillary permanent central incisors was selected. Periapical radiographs taken before and after orthodontic treatment were digitized and imported to the Regeemy software. Based on an analysis of the posttreatment radiographs, the length of the incisors was measured using Image J software. The mean EARR was described in pixels and relative root resorption (%). The patient's age and gender, tooth extraction, use of elastics, and treatment duration were evaluated to identify possible correlations with EARR. RESULTS: The mean EARR observed was 15.44±12.1 pixels (5.1% resorption). No differences in the mean EARR were observed according to patient characteristics (gender, age) or treatment parameters (use of elastics, treatment duration). The only parameter that influenced the mean EARR of a patient was the need for tooth extraction. CONCLUSION: A posteriori registration and subtraction of periapical radiographs was a suitable method to quantify EARR after orthodontic treatment, and the need for tooth extraction increased the extent of root resorption after orthodontic treatment.

Influence of radiant exposure values from two third generation LED curing units on polymerization profile and microhardness of orthodontic composite under ceramic and metallic brackets

ABSTRACT Introduction: Third generation of LED light curing units might be used in short exposure periods for orthodontic brackets bonding. Objective: This study evaluated the effect of the different radiant exposure (RE) values: Manufacturers' instructions (MI), ½ MI, 1/4 MI and Turbo mode. Two third-generation LED curing units were used: VALO® and Bluephase 20i® . The degree of conversion (DC) and Vickers hardness (VHN) of an orthodontic composite (OC) (Transbond XT) under metallic (MB) or ceramic brackets (CB) were measured. Methods: OC was applied to the bracket base, which was then placed over an attenuated total reflectance (ATR) table coupled to an infrared light spectroscope, or to a glass surface for the VHN analysis. The specimens were light-cured and DC values were calculated. The VHN was obtained in a microhardness tester. The data were analyzed with 2-way ANOVA followed by Tukey's post-hoc test (pre-set α=0.05). Linear regression analysis evaluated the relationship between RE values and dependent variables. Results: CB allowed higher DC and VHN values than MB (p< 0.001). No significant difference was noted among groups when CB were used. For MB, MI groups showed the highest DC and VHN values. A significant, but weak relationship was found between delivered RE values and dependent variables. Conclusions: The decrease in RE values from third generation LED CU did not jeopardize the DC values when CB were used, but can compromise DC and VHN values when MB are used.

RESUMO Introdução: A terceira geração de LEDs fotopolimerizadores pode ser utilizada em curtos períodos de exposição para a colagem de braquetes ortodônticos. Objetivo: O presente estudo avaliou o efeito dos diferentes valores de irradiância (IR): instruções do fabricante (IF), ½ IF, » IF e modo Turbo. Dois fotopolimerizadores LED de terceira geração (VALO® e Bluephase20i®) foram utilizados. Foram mensurados o grau de conversão (GC) e a dureza Vickers (VHN) de um compósito ortodôntico (CO) (Transbond XT) sob braquetes metálicos (BM) ou cerâmicos (BC). Métodos: O compósito ortodôntico foi aplicado na base do braquete e foi posicionado sobre uma mesa de refletância total atenuada (ATR) acoplada a um espectroscópio de infravermelho ou a uma superfície de vidro para análise de VHN. As amostras foram fotopolimerizadas e os valores de GC foram calculados. O VHN foi obtido em um microdurômetro. Os dados foram analisados com ANOVA de 2 fatores seguida do teste post-hoc de Tukey (predefinido α = 0,05). A análise de regressão linear avaliou a relação entre os valores de IR e as variáveis dependentes. Resultados: BC permitiu valores maiores de GC e VHN do que BM (p<0,001). Nenhuma diferença significativa foi observada entre os grupos quando BC foi utilizado. Para BM, os grupos de IF mostraram os maiores valores de GC e VHN. Uma relação significativa, mas fraca, entre os valores de IR entregue e as variáveis dependentes foi encontrada. Conclusões: A diminuição dos valores de IR dos fotopolimerizadores LED de terceira geração não prejudicou os valores de GC quando BC foram utilizados, mas pode comprometer os valores de GC e VHN quando BM são utilizados.

Direct measurement of time-dependent anesthetized in vivo human pulp temperature.

OBJECTIVES: Human intrapupal tooth temperature is considered to be similar to that of the body (≈37 °C), although the actual temperature has never been measured. This study evaluated the in vivo, human, basal, coronal intrapulpal temperature of anesthetized upper first premolars. METHODS: After approval of the local Ethics Committee was obtained (protocol no. 255,945), upper right and left first premolars requiring extraction for orthodontic reasons from 8 volunteers, ranging from 12 to 30 years old, received infiltrative and intraligamental anesthesia. The teeth (n=15) were isolated using rubber dam and a small, occlusal preparation was made using high-speed handpiece, under constant air-water spray, until a minute pulp exposure was attained. The sterile probe from a wireless, NIST-traceable, temperature acquisition system (Thermes WFI) was inserted directly into the coronal pulp. Once the probe was properly positioned and stable, real-time temperature data were continuously acquired for approximately 25 min. Data (°C) were subjected to 2-tailed, paired t-test (α=0.05), and the 95% confidence intervals for the initial and 25-min mean temperatures were also determined. RESULTS: The initial pulp temperature value (31.8±1.5 °C) was significantly lower than after 25-min (35.3±0.7 °C) (p<0.05). The 95% confidence interval for the initial temperature ranged from 31.0 to 32.6 °C and from 35.0 to 35.7 °C after 25 min. A slow, gradual temperature increase was observed after probe insertion until the pulp temperature reached a plateau, usually after 15 min. SIGNIFICANCE: Consistent coronal, human, in vivo temperature values were observed and were slightly, but significantly below that of body core temperature.

In vivo temperature rise in anesthetized human pulp during exposure to a polywave LED light curing unit.

OBJECTIVES: This in vivo study evaluated pulp temperature (PT) rise in human premolars during exposure to a light curing unit (LCU) using selected exposure modes (EMs). METHODS: After local Ethics Committee approval, intact first upper premolars, requiring extraction for orthodontic reasons, from 8 volunteers, received infiltrative and intraligamental anesthesia. The teeth (n=15) were isolated using rubber dam and a minute pulp exposure was attained. A sterile probe from a wireless, NIST-traceable, temperature acquisition system was inserted directly into the coronal pulp chamber, and real time PT (°C) was continuously monitored while the buccal surface was exposed to polywave light from a LED LCU (Bluephase 20i, Ivoclar Vivadent) using selected EMs allowing a 7-min span between each exposure: 10-s either in low (10-s/L) or high (10-s/H); 5-s-turbo (5-s/T); and 60-s-high (60-s/H) intensities. Peak PT values and PT increases from baseline (ΔT) after exposure were subjected to one-way, repeated measures ANOVAs, and Bonferroni's post hoc tests (α=0.05). Linear regression analysis was performed to establish the relationship between applied radiant exposure and ΔT. RESULTS: All EMs produced higher peak PT than the baseline temperature (p<0.001). The 60-s/H mode generated the highest peak PT and ΔT (p<0.001), with some teeth exhibiting ΔT higher than 5.5°C. A significant, positive relationship between applied radiant exposure and ΔT (r(2)=0.916; p<0.001) was noted. SIGNIFICANCE: Exposing intact, in vivo anesthetized human upper premolars to a polywave LED LCU increases PT, and depending on EM and the tooth, PT increase can be higher than the critical ΔT, thought to be associated with pulpal necrosis.

Comparison of in vivo and in vitro models to evaluate pulp temperature rise during exposure to a Polywave® LED light curing unit

Abstract Objectives: To measure and compare in vivo and in vitro pulp temperature (PT) increase (ΔTEMP) over baseline, physiologic temperature using the same intact upper premolars exposed to the same Polywave® LED curing light. Methodology: After local Ethics Committee approval (#255,945), local anesthesia, rubber dam isolation, small occlusal preparations/minute pulp exposure (n=15) were performed in teeth requiring extraction for orthodontic reasons. A sterile probe of a temperature measurement system (Temperature Data Acquisition, Physitemp) was placed within the pulp chamber and the buccal surface was sequentially exposed to a LED LCU (Bluephase 20i, Ivoclar Vivadent) using the following exposure modes: 10-s low or high, 5-s Turbo, and 60-s high. Afterwards, the teeth were extracted and K-type thermocouples were placed within the pulp chamber through the original access. The teeth were attached to an assembly simulating the in vivo environment, being similarly exposed while real-time temperature (°C) was recorded. ΔTEMP values and time for temperature to reach maximum (ΔTIME) were subjected to two-way ANOVA and Bonferroni's post-hoc tests (pre-set alpha 0.05). Results: Higher ΔTEMP was observed in vitro than in vivo. No significant difference in ΔTIME was observed between test conditions. A significant, positive relationship was observed between radiant exposure and ΔTEMP for both conditions (in vivo: r2=0.917; p<0.001; in vitro: r2=0.919; p<0.001). Conclusion: Although the in vitro model overestimated in vivo PT increase, in vitro PT rise was close to in vivo values for clinically relevant exposure modes.

Effects of diferent salivary ph on the surface and roughness of different orthodontic wires

AIM: The aim of this study was to evaluate the effects of different salivary pH on the surface of orthodontic wires. MATERIAL AND METHODS: Two hundred and seventy wire segments of titanium-molybdenum alloy (TMA), and Cr-Ni stainless steel , subjected to saliva pH 2.0 , 5.0 and 7.6 , in three different times of storage, divided into 3 groups (n=30). Group 1: TMA (Morelli), Group 2: TMA (Ormco) and Group 3: Stainless steel Cr-Ni (Morelli). To read the roughness profilometer was used Mitutoyo Surftest Digital-301. Observation of the surface morphology was performed by scanning electron microscope (SEM). RESULTS: Between the results is that the lower the pH more roughness was found. No changes were observed on the wires roughness of group 3. In the evaluation of SEM, changes were found in surface TMA wires in pH 2 and 5, the steel wires no changes superficias. CONCLUSION: The acidic pH and time showed effects on TMA's wires. The stainless steel wires showed no changes. We conclude that the stainless wires have greater resistance to salivary pH.

Cytokine expression pattern in compression and tension sides of the periodontal ligament during orthodontic tooth movement in humans.

Orthodontic tooth movement is achieved by the remodeling of periodontal ligament (PDL) and alveolar bone in response to mechanical loading and is believed to be mediated by several host mediators, such as cytokines. By means of real-time polymerase chain reaction (PCR), we studied the pattern of expression of mRNA encoding several pro- and anti-inflammatory cytokines in relation to several extracellular matrix and bone remodeling markers, in tension (T) and compression (C) sides of the PDL of human teeth subjected to rapid maxillary expansion. The PDL of normal teeth was used as a control. The results showed that both T and C sides exhibited significantly higher expression of all targets when compared with controls, except for type I collagen (COL-I) and tissue inhibitor of metalloproteinase-1 (TIMP-1) on the C side. Comparing C and T sides, the C side exhibited higher expression of tumor necrosis factor-alpha (TNF-alpha), receptor activator of nuclear factor-kappaB ligand (RANKL), and matrix metalloproteinase-1 (MMP-1), whereas the T side presented higher expression of interleukin-10 (IL-10), TIMP-1, COL-I, osteoprotegerin (OPG), and osteocalcin (OCN). The expression of transforming growth factor-beta (TGF-beta) was similar in both C and T sides. Our data demonstrate a differential expression of pro- and anti-inflammatory cytokines in compressed and stretched PDL during orthodontic tooth movement.

Rebonding of unused brackets with different orthodontic adhesives

OBJECTIVE: To compare in vitro shear bond strength (SBS) of different orthodontic adhesives in bonding and repeatedly rebonding metal brackets, and to evaluate the bond failure site with the adhesive remnant index (ARI). METHODS: Specimens consisted of 90 extracted human first premolars, randomly divided into three groups (n=30). The adhesives Alpha Plast (AP), ConciseTM (CO) and TransbondTM XT (TB) were used in each group. Three SBS tests were performed, i.e., one at T0 (initial) and the other two at T1 and T2 (first and second rebondings, respectively), observing a 24-hour interval. The tests were performed in a Shimadzu AG-I (10kN) SBS testing machine, at a speed of 0.5 mm/min. RESULTS: SBS data were subjected to ANOVA, Tukey's test and Bonferroni test (p<0.05). For the ARI, the Kruskal Wallis test was performed, followed by the Dunn test. The results revealed that at T0 groups AP and CO showed SBS values that were near, but above TB values; and at T1 and T2, the highest SBS values were observed for the AP group, followed by the CO and TB groups. CONCLUSION: Statistically significant differences were found in SBS between groups AP, CO and TB during bonding and repeated rebondings of unused metal brackets, with group AP achieving the highest SBS value. Regarding ARI, adhesive AP exhibited bond failure at the enamel-adhesive interface, with a higher enamel fracture frequency.

Tratamento da mordida aberta anterior com miniplacas / Treatment of anterior open bite with miniplates

Este artigo reporta o caso clínico de um paciente do gênero feminino, com 53 anos, portadora de má oclusão Classe II subdivisão esquerda, com mordida aberta anterior esquelética. O tratamento foi realizado com a intrusão dos dentes posteriores superiores e inferiores, por meio da ancoragem esquelética com quatro miniplacas. Os resultados demonstraram a intrusão dos molares superiores e inferiores, distalização dos molares superiores do lado esquerdo, rotação anti-horária da mandíbula, com diminuição da altura facial inferior, correção da mordida aberta anterior e da Classe II subdivisão esquerda.

This article reports the clinical case of a 53 years old female patient, with Angle Class II subdivision left, with skeletal anterior open bite. The treatment was performed with the intrusion of maxillary and mandibular posterior teeth, by skeletal anchorage with four miniplates. The results showed the intrusion of upper and lower molars distalization of upper molars on the left, counterclockwise rotation of the mandible, with decreased lower facial height, correction of anterior open bite, and Class II subdivision left.

Avaliação da resistência ao cisalhamento de braquetes colados com resinas ortodônticas fluoretadas / Evaluation of shear bond strength of brackets bonded with orthodontic fluoride-releasing composite resins

OBJETIVO: avaliar a resistência ao cisalhamento de braquetes metálicos colados com resinas que contêm flúor, comparando-as a uma resina convencional; e analisar a quantidade de adesivo remanescente na superfície do esmalte. MÉTODOS: sessenta pré-molares foram divididos aleatoriamente em 3 grupos: Grupo I - Concise (3M), Grupo II - Ultrabond (Aditek do Brasil) e Grupo III - Rely-a-Bond (Reliance). Após a colagem dos braquetes, as amostras foram termocicladas (500 ciclos) nas temperaturas de 5°C e 55°C. Após 48 horas, foram submetidas aos ensaios mecânicos de cisalhamento na direção oclusocervical, com velocidade de carga de 0,5mm/min, em uma máquina MTS 810. RESULTADOS: foram observadas resistências médias ao cisalhamento de 24,54±6,98MPa para o Grupo I, de 11,53±6,20MPa para o Grupo II e de 16,46±5,72MPa para o Grupo III. A Análise de Variância determinou diferença estatística entre as médias de resistência ao cisalhamento entre os grupos (p < 0,001). O teste de Tukey evidenciou que as médias dos três grupos foram significativamente diferentes entre si (p < 0,05), com a maior resistência para o Grupo I e a menor para o Grupo II. O teste de Kruskal-Wallis não mostrou diferença estatística significativa na quantidade de adesivo remanescente entre os grupos (p = 0,361). CONCLUSÃO: todos os materiais apresentaram resistência adesiva adequada para uso clínico, com maior resistência ao cisalhamento para a resina Concise, sem diferenças significativas para o Índice de Adesivo Remanescente entre os grupos.

OBJECTIVE: To evaluate the shear bond strength of stainless steel brackets bonded with fluoride releasing composite resins, comparing them with a conventional resin and to analyze the amount of resin left on the enamel surface. METHODS: Sixty premolars were randomly divided into three groups: Group I - Concise (3M), Group II - Ultrabond (Aditek do Brasil) and Group III - Rely-a-Bond (Reliance). After bonding, the samples were thermocycled (500 cycles) at 5ºC and 55ºC temperatures. After 48 hours they were subjected to shear bond strength testing, in the occluso-gingival direction, using an MTS 810 Universal Testing Machine with load speed of 0.5 mm/min. RESULTS: The results demonstrated a mean shear bond strength of 24.54 ± 6.98 MPa for Group I, 11.53 ± 6.20 MPa for Group II, and 16.46 ± 5.72 MPa for Group III. Analysis of Variance (ANOVA) determined a statistical difference in the mean shear bond strengths between groups (p < 0.001). The Tukey test evidenced that the averages of the three groups were significantly different (p < 0.05), with the highest values for Group I and the lowest for Group II. The Kruskal-Wallis test did not show significant differences in the amount of resin left on the enamel in any of the three groups (p = 0.361). CONCLUSION: All materials exhibited adequate adhesive bond strength for clinical use. Concise exhibited the highest degree of shear bond strength but no significant differences were found in Adhesive Remnant Index (ARI) between the groups.

Análise da maturação óssea em pacientes de 13 a 20 anos de idade por meio de radiografias de punho / Analysis of skeletal maturation in patients aged 13 to 20 years by means of hand wrist radiographs

OBJETIVO: avaliar um método alternativo e simplificado de tomada radiográfica, oportunizando aos implantodontistas e ortodontistas verificarem o término do crescimento ósseo, bem como as diferenças existentes entre os gêneros, em uma amostra de indivíduos de 13 a 20 anos de idade. MÉTODOS: utilizou-se uma tomada radiográfica do punho, onde foi empregada película radiográfica oclusal, para avaliar a maturação do osso rádio. Foram avaliados 160 pacientes de ambos os gêneros, divididos em grupos de 10 indivíduos. As radiografias obtidas foram examinadas por cinco avaliadores especialistas em Ortodontia devidamente calibrados. RESULTADOS: verificou-se que houve uma correlação positiva entre a idade cronológica dos pacientes e a sua idade biológica, além de o gênero feminino possuir uma maturação óssea anterior ao gênero masculino. CONCLUSÃO: esse método pode determinar o estágio de maturação do osso rádio, possibilitando um meio de diagnóstico acessível e rápido na determinação da idade óssea correta para instalação de um implante e dispositivo ortodôntico.

AIM: Evaluate an alternative and simplified radiographic method, giving opportunities to orthodontists and implantodontists to verify the completion of bone growth as well as differences between genders in a sample of individuals 13 to 20 years old. METHODS: It was used a wrist radiography, registered in a occlusal radiographic film, to assess the maturation of the radius bone. Were studied 160 patients of both genders, divided into groups of 10 individuals. The radiographs were examined by five specialists in Orthodontics evaluators properly calibrated. RESULTS: Indicated that there was a positive correlation between the chronological age of the patients and their biological age, and the females have bone maturation earlier than males. CONCLUSION: This method can determine the stage of maturation of the radius bone, allowing an affordable and rapid diagnosis method to determine the correct bone age for installation of an implant and orthodontic appliance.

Influência de diferentes tipos de máquinas de ensaio e da termociclagem na resistência adesiva ao cisalhamento e no índice de adesivo remanescente / Influence of different types of mechanical testing and thermocycling on shear bond strength and the adhesive remnant index

Este estudo comparou duas diferentes máquinas de ensaio mecânico (Shimadzu e Kratos), com ou sem a realização da termociclagem, na leitura da resistência adesiva ao cisalhamento (RAC) e do índice de adesivo remanescente (IAR) após a descolagem de bráquetes metálicos colados com resina Transbond XT. Foram utilizados 60 pré-molares humanos, nos quais foram colados bráquetes metálicos, divididos aleatoriamente em dois grupos: Grupo I – com termociclagem (500 ciclos) entre 5º e 55ºC e Grupo II – sem termociclagem. Estes grupos foram subdivididos em quatro subgrupos (n=15). Foi realizado o teste mecânico de cisalhamento com ambas as máquinas: subgrupos I A (Shimadzu) e I B (Kratos) e subgrupos II A (Shimadzu) e II B (Kratos). As amostras foram submetidas aos ensaios mecânicos de cisalhamento com velocidade de carga de 0,5 mm/min. Os resultados da RAC foram submetidos ao teste de normalidade de D’Agostino & Pearson, ANOVA - 1 Critério (a = 0,05), pós-teste de Tukey e os dados do IAR ao teste de Kruskal-Wallis (a = 0,05). Não foram encontradas diferenças estatisticamente significativas entre os subgrupos. Conclui-se que a utilização de diferentes tipos de máquinas de ensaio, com ou sem termociclagem, não apresentam diferenças estatísticas na leitura da resistência ao cisalhamento ou do índice de adesivo remanescente...

This study has compared two different mechanical testing machine (Shimadzu and Kratos), with or without performing of thermocycling, the reading of the adhesive shear strength (RAC) and the adhesive remnant index (ARI), after debonding of metal brackets bonded with Transbond XT resin. Metal brackets were bonded on sixty human premolars that were then randomly divided into two groups: Group I - with thermocycling (500 cycles) between 5 and 55ºC and Group II - without thermocycling. These groups were divided into four subgroups (n = 15). Test was performed with both mechanical shearing machines: subgroups I A (Shimadzu) and I B (Kratos) and subgroups II A (Shimadzu) and II B (Kratos). Samples were submitted to shear bond strength (SBS) testing with a crosshead speed of 0.5 mm/min. The results of the SBS were tested for normality D’Agostino & Pearson, test 1 way ANOVA (a = 0.05), Tukey post-test. Data from the ARI were submitted to the Kruskal-Wallis test (a = 0.05). There was no statistically significant difference between subgroups. There was no statistically significant difference between subgroups. It was concluded that the use of different types of test machines, with or without thermocycling did not show statistical differences in reading shear bond strength or adhesive remnant index...

Avaliação do esmalte dentário após recolagens de bráquetes metálicos e cerâmicos / Evaluation of dental enamel after rebonding of metal and ceramic brackets

Na descolagem de bráquetes ortodônticos pode ocorrer a perda de esmalte na interface adesivo-esmalte. O objetivo deste estudo foi avaliar os possíveis danos à superfície do esmalte com recolagens de bráquetes metálicos e cerâmicos novos por meio da resistência adesiva ao cisalhamento (RAC), da análise do índice de adesivo remanescente (IAR), da avaliação da rugosidade de superfície (RA) e pela análise de microscopia eletrônica (MEV). Foram usados 120 pré-molares, divididos aleatoriamente em 4 grupos de 30 dentes: CS (Controle Saliva); CA (Condicionamento Ácido); M (Metálico) e C (Cerâmico). Foram colados 120 bráquetes metálicos e 120 cerâmicos, para os grupos M e C, em quatro tempos. Os ensaios mecânicos foram realizados em máquina SHIMADZU, na velocidade 0,5 mm/min. Na avaliação da RAC, o ANOVA a dois critérios demonstrou não haver diferenças (p= 0,052) entre os grupos. Na avaliação do IAR, o teste U de Mann-Whitney demonstrou diferença entre os grupos (p< 0,001), onde o grupo cerâmico exibiu escores mais altos que o metálico. Para a rugosidade, o ANOVA a um critério demonstrou que o grupo M apresentou maior RA (p< 0,001). O teste de Tukey demonstrou que os grupos M e C, após o polimento com discos Sof-Lex, exibiram valores de rugosidade inferiores aos demais grupos. Conclui-se que na remoção de bráquetes metálicos ou cerâmicos e da resina remanescente existe maior risco de danos ao esmalte nas recolagens sucessivas. O polimento com discos Sof-Lex promoveu superfície com maior lisura do esmalte.

Debonding of orthodontic brackets may cause enamel surface loss primarily at the adhesive-enamel interface. The purpose of the present study was to evaluate by means of shear bond strength (SBS), adhesive remnant index (ARI), assessment of surface roughness and electron microscope analysis, the possible damages at enamel surface with repeated rebonding of new metallic and ceramic brackets. One hundred and twenty human premolars were randomly divided into 4 groups of 30 premolars each: CS (Saliva Control); CA (Acid Etching); M (Metal); C (Ceramic). For CA group, 4 repeated acid conditionings were performed. One hundred and twenty metallic and ceramic brackets, for groups M and C, were bonded and rebonded respectively at 4 stages. Mechanical trials were obtained with a SHIMADZU testing machine at 0.5 mm/min cross-speed. The SBS results were statistically tested with ANOVA, and no statistically significant differences (p=0.052) were observed. The ARI was evaluated by Mann-Whitney test, which demonstrated that there was a statistically significant difference between metallic and ceramic brackets (p<0.001). The ceramic group exhibited higher statistically significant scores for ARI than the metallic group. The roughness assessment was made with one-way ANOVA, that showed statistically significant differences between groups (p<0.001). Tukey´s test has demonstrated that the M and C groups that were polished with SofLex discs had statistically significant lower roughness values as compared to other groups. Polishing with Sof-lex discs, lead to increased smoothness of enamel surfaces.

Microdureza Vickers e grau de conversão em resinas ortodônticas / Vickers microhardness and degree of conversion on orthodontic adhesives

O objetivo deste estudo foi avaliar em diferentes resinas ortodônticas a microdureza Vickers e o grau de conversão. Quatro resinas foram utilizadas: Orthobond (OB), Ortholite (OL), Concise (CO) e Transbond XT (TB). Para cada resina, cinco amostras foram obtidas, nas quais foram realizadas trinta endentações em cada superfície no microdurômetro Shimadzu (carga de 300 gramas/15 segundos). Para a avaliação do grau de conversão, duas amostras de cada monômero e polímero foram obtidas e submetidas ao ensaio de FTIR pelo método de transmissão, com resolução 2 cm-1 e 40 varreduras. Os resultados de microdureza Vickers (µHV) e grau de conversão (%) foram, respectivamente, para OB: 46 ± 17.52 (70% ±1.41), OL: 71 ±28.15 (61% ±3.53), CO: 76 ±32.70 (70% ±0.35) e TB: 73±28.40 (60% ±9.89). Os dados da µHV foram submetidos ao Teste de ANOVA e pós teste de Tukey, não apresentando diferenças estatísticas significantes entre as resinas. O conhecimento das propriedades físicas entre as resinas pode facilitar a escolha do material utilizado nos procedimentos ortodônticos.

The aim of this study was to evaluate Vickers microhardness and the degree of conversion of different orthodontic resins. Four resins were used: Orthobond (OB), Ortholite (OL), Concise (CO), and Transbond XT (TB). For each resin five samples were obtained, in which thirty indentations were made on each surface in Shimadzu microhardness (300 grams/15 seconds). To assess the degree of conversion, two samples of each monomer and polymer materials were obtained and submitted to the test of FTIR Spectrophotometry by method of transmission, toned down with resolution 2 cm-1 and 40 scans. The results of Vickers microhardness (µ HV) and degree of conversion (%) were, respectively OB: 46 ± 17.52 (70% ± 1.41); OL: 71 ± 28.15 (61% ± 3.53); CO: 76 ± 32.70 (70% ± 0.35); TB: 73 ± 28.40 (60% ± 9.89). The data were submitted to ANOVA test and Tukey post-test, and no significant statistical differences were observed between the resins. The knowledge of the physical properties between resins can facilitate the choice of the material used in orthodontic procedures.