Transition temperature range of thermally activated nickel-titanium archwires

Objectives: The shape memory resulting from the superelasticity and thermoelastic effect is the main characteristic of thermally activated NiTi archwires and is closely related to the transition temperature range (TTR). The aim of this study was to evaluate the TTR of thermally activated NiTi archwires commercially available. Material and Methods: Seven different brands of 0.019"x0.025" thermally activated nickel-titanium archwires were tested as received by differential scanning calorimetry (DSC) over the temperature range from -100°C to 150°C at 10°C/min. Results: All thermally activated NiTi archwires analyzed presented stage transformation during thermal scanning with final austenitic temperature (Af) ranging from 20.39°C to 45.42°C. Three brands of NiTi archwires presented Af close to the room temperature and, this way, do not present properties of shape memory and pseudoelasticity that are desirable in clinical applications. Conclusions: The thermally activated NiTi archwires present great variability in the TTR and the elastic parameters of each NiTi archwire should be provided by the manufacturers, to allow achievement of the best clinical performance possible

Comparison of compensatory class III malocclusion treatment changes with two prescriptions of preadjusted brackets

Objective: This retrospective study aimed to compare Class III malocclusion treatment changes performed with two different preadjusted bracket prescriptions: Biofunctional and Roth. Material and Methods: The sample comprised 84 Class III malocclusion patients treated with compensatory approaches. The sample was divided into 2 groups: Group 1 (Biofunctional): 36 patients (23 female, 13 male) with a mean initial age of 20.04 years and a mean treatment time of 2.53 years. Group 2 (Roth): 48 patients (28 female and 20 male) with a mean initial age of 19.05 years and a mean treatment time of 2.64 years. Intergroup comparisons at the pre- (T1) and posttreatment (T2) stages and of the treatment changes (T2-T1) were performed with t tests. Results: There were greater maxillary and mandibular incisors labial and lingual tipping and greater occlusal plane counterclockwise rotation in the Roth than in the Biofunctional prescription. Conclusion: Compensatory Class III malocclusion treatment performed with the Biofunctional prescription minimizes the side effects of Class III elastics.Objetivo: este estudo retrospectivo teve como objetivo comparar as alterações do tratamento da má-oclusão de Classe III com duas prescrições diferentes de bráquetes preajustados: Biofuncional e Roth. Metodologia: a amostra consistiu em 84 pacientes com má-oclusão de Classe III tratados com abordagens compensatórias. A amostra foi dividida em 2 grupos: Grupo 1 (Biofuncional): 36 pacientes (23 mulheres, 13 homens) com idade inicial média de 20,04 anos e um tempo médio de tratamento de 2,53 anos. Grupo 2 (Roth): 48 pacientes (28 mulheres e 20 homens) com idade inicial média de 19,05 anos e um tempo médio de tratamento de 2,64 anos. As comparações intergrupo ao início (T1) e ao fim do tratamento (T2) e as alterações do tratamento (T2-T1) foram feitas com testes t. Resultados: houve uma maior vestibularização dos incisivos superiores e inferiores, retroclinação dos incisivos inferiores e uma maior rotação anti-horária do plano oclusal na prescrição Roth do que na Biofuncional. Conclusão: o tratamento compensatório da má-oclusão de Classe III feito com a prescrição Biofuncional minimiza os efeitos colaterais do elástico de Classe III

Comparison of torque expression in esthetic brackets

The objective of this work is to test the null hypothesis that there is no difference in the torque expression among different esthetic brackets. Five ceramic self-ligating brackets (In-Ovation C ? GAC, Damon Clear?Ormco, QuicKlear-Forestadent, Click-It -TP Orthodontics, Clarity SL-3M Unitek) and 4 ceramic conventional brackets (Inspire Ice?Ormco, InVu Ceramic-TP Orthodontics, Ceramic Roth?Morelli, Clarity Metal-Reinforced Ceramic Bracket-3M Unitek) were selected. Metallic Damon MX self-ligating bracket (Ormco) was used as control. Third-order moments were measured at 12º, 24º and 36º using an archwire torsion device associated with a Universal Testing Machine (EMIC DL2000), with 0.019x0.025-inch stainless steel wire. Anova followed by Tukey tests were used for intergroup comparisons. In all tested angulations the Damon Clear bracket presented the highest torque expression, followed by Clarity, Clarity SL and Damon Mx brackets, with the worst torque expression shown by the InVu Ceramic bracket. The InVu Ceramic demonstrated the largest while the Damon Clear brackets demonstrated the smallest slot height and clearance. The null hypothesis was rejected since torque expression was different among the esthetic brackets evaluated. It was also concluded that the slot height is directly related to torque expression

Comparison of the facial profile attractiveness in Class III borderline patients after surgical or compensatory orthodontic treatment

Background: This study aimed to compare the facial profile attractiveness of Class III borderline patients after surgical or compensatory orthodontic treatment. Material and Methods: The sample consisted of 60 borderline Class III malocclusion patients, divided into two groups: Group 1 (Surgical): 30 patients (16 male; 14 female) treated with orthodontic fixed appliances and bimaxi-llary orthognathic surgery. Mean initial age was 20.05 years (s.d.=2.40) and mean treatment time was 2.23 years (s.d.=0.82). Group 2 (Compensatory): 30 patients (13 male; 17 female) treated compensatorily with fixed applian-ces and Class III elastics. Mean initial age was 18.53 years (s.d.=4.35) and mean treatment time was 2.08 years (s.d.=0.67). Silhouettes of the facial profile were constructed obtained from the pretreatment and posttreatment lateral cephalograms and evaluated by orthodontists (N=41, 22 females and 19 males, mean age of 35.65 years), assigning scores from 1 (least attractive) to 10 (most attractive). Intergroup comparison of profile attractiveness was performed by Mann-Whitney test. For intragroup comparison of initial and final stages, the Wilcoxon test was used. Results: At initial stage, the compensatory group presented a statistically significant greater attractiveness of the profile than the surgical group. With treatment, the surgical group presented significantly more improvement in facial profile than the compensatory group. At the final stage, profile attractiveness of surgical and compensatory groups was similar. Conclusions: The facial profile attractiveness is similar in Class III patients after orthognathic surgery or com-pensatory orthodontic treatment. However, surgery provided more improvement in profile attractiveness than the compensatory treatment in Class III patients

Prospective study of dentoskeletal changes in class II division malocclusion treatment with twin force bite corrector

Objective: To evaluate the dentoskeletal changes of Class II malocclusion treatment with the Twin Force Bite Corrector (TFBC). Materials and Methods: The sample comprised 86 lateral cephalograms obtained from 43 subjects with Class II division 1 malocclusion; the subjects were divided into two groups. The experimental group comprised 23 patients with a mean initial age of 12.11 years who were treated with the TFBC for a mean period of 2.19 years. The control group included 40 lateral cephalograms from 20 Class II nontreated patients, with an initial mean age of 12.55 years and a mean observation period of 2.19 years. The lateral cephalograms were evaluated before and after orthodontic treatment in group 1 and in the beginning and end of the observation period in group 2. t-Tests were used to compare the initial and final cephalometric characteristics of the groups as well as the amount of change. Results: The experimental group presented greater maxillary growth restriction and mandibular retrusion than the control group, as well as greater maxillomandibular relationship improvement and greater labial tipping of the mandibular incisors. The results also showed a greater decrease in overbite and overjet in the experimental group, and there were no statistically significant differences in the craniofacial growth pattern between groups. Conclusions: The TFBC promotes restriction of anterior maxillary displacement without significant changes in mandibular length and position and improvement of maxillomandibular relationship without changes in facial growth and significant buccal tipping of mandibular incisors. Class II correction with the TFBC occurred primarily as a result of dentoalveolar changes

Comparison of the Force Released by Intermaxillary Elastics Used for Different Time Periods

Objective:The objective of the present study was to compare the strength degradation of the force of intermaxillary elastic used for different periods.Methods:The sample included intermaxillary elastics used for 20 adult patients with bilateral Class II or III malocclusion in orthodontic treatment with fixed appliances, with a mean age of 27.25 years. Latex orthodontic elastics with 3/16 inch of diameter were used, with an average stretching of three times its diameter. The elastics were used in the same patient bilaterally for different periods, with each pair of elastics used for 1, 12, 24, and 48h. Thus, the sample consisted of 200 elastics, with 40 being used in each period (one pair used by each patient) and 40 new elastics without use tested as control. Elastics were tested using a universal testing machine, stretched with a velocity of 30 mm/min, and the force was evaluated in stretches of 15, 20, 25, and 30 mm. The degradation force was compared in the four different times of use and control by one-way ANOVA (analysis of variance) and Tukey tests.Results:There were significant differences among the groups in all evaluated stretches (15, 20, 25, and 30 mm). The control elastics presented higher average forces numerically and statistically significant for all tested times, except for the elastic used for 1h. The elastics used for 1, 12, and 24h had similar forces among them, with a significant difference to the elastics used for 48h.Conclusion:It is recommended to change the intermaxillary elastics after 24 h of use

Comparative study of the chronology of eruption of permanent teeth and calcification of second molars in Angle Class I and Class II malocclusions.

O objetivo deste estudo foi comparar a cronologia de erupção dos dentes permanentes e os estágios de calcificação dos segundos molares nas másoclusões de Classe I e Classe II de Angle e avaliar a existência de correlação entre esses estágios de calcificação e as grandezas cefalométricas SNA, SNB, ANB, Co-A e Co-Gn. Para avaliar a cronologia de erupção dos dentes permanentes (com exceção dos terceiros molares), foram utilizados 527 pares de modelos de gesso de jovens na faixa etária dos 5 aos 13 anos de idade que foram divididos em dois grupos. O grupo 1 ficou constituído por modelos de gesso que apresentassem uma relação molar de Classe I de Angle, e o grupo 2, por aqueles que apresentassem uma relação molar de Classe II de Angle. A idade média de erupção dos dentes permanentes foi determinada pelo método de Karber. A comparação entre os grupos foi realizada por meio do teste t independente. Para avaliar os estágios de calcificação dos segundos molares e a existência de correlação com as grandezas cefalométricas SNA, SNB, ANB, Co-A e Co-Gn, foram utilizadas 60 radiografias panorâmicas e 60 telerradiografias em norma lateral dos mesmos jovens, obtidas aos 8 anos de idade. Estas radiografias também foram divididas em dois grupos. O grupo 1 ficou constituído por radiografias de jovens com relação molar de Classe I de Angle e o grupo 2 por radiografias de jovens com relação molar de Classe II de , Angle. Os estágios de calcificação dos segundos molares foram determinados pelo método de NOLLA. A comparação entre os grupos foi realizada por meio do teste não paramétrico de Mann-Whitney. Os resultados mostraram que, de uma maneira geral, os indivíduos com relação molar de Classe I de Angle apresentam idades de erupção dos dentes permanentes mais precoces que os indivíduos com relação molar de Classe II de Angle, e esta diferença foi estatisticamente significante para todos os segundos molares, além dos dentes 15, 23, 34 e 45. Não houve diferença estatisticamente significante entre os estágios de calcificação dos segundos molares nos grupos considerados e não houve correlação entre as variáveis cefalométricas estudadas e os estágios de calcificação em nenhum dos grupos.The objective of this study was to compare the chronology of eruption of permanent teeth and the stages of calcification of the second molars in Angle Class I and Class II malocclusions, as well as to investigate if there is any correlation between these stages of calcification and the cephalometric measurements SNA, SNB, ANB, Co-A, Co-Gn. For evaluation of the chronology of eruption of permanent teeth (except for the third molars), 527 pairs of dental casts of young subjects aged 5 to 13 years old were employed, which were divided in two groups. Group 1 comprised dental casts presenting Angle Class I molar relationship, whereas Group 2 included those displaying an Angle Class II molar relationship. The mean age of eruption of the permanent teeth was determined by means of the Karbers method. Comparison between groups was evaluated by the independent t test. For evaluation of the stages of calcification of the second molars and presence of correlation with the cephalometric measurements SNA, SNB, ANB, Co-A, Co-Gn, 60 panoramic radiographs and 60 lateral cephalograms of the same subjects were used, which had been obtained at 8 years old. These radiographs were also divided in two groups. Group 1 comprised radiographs of young individuals presenting Class I molar relationship, and Group 2 involved subjects with Class II molar relationship. The stages of calcification of the second molars were determined as suggested by Nolla. Comparison between groups was accomplished through the nonparametric Mann-Whitneys test. The results demonstrated that, in general, individuals presenting Class I molar relationship presented earlier mean ages of eruption of the permanent teeth when compared to those subjects with Class II molar relationship. This difference was statistically significant for all second molars, as well as for the teeth 15, 23, 34 and 45. No statistically significant differences could be found between the stages of calcification of the second molars in the evaluated groups; moreover, there was no correlation between the cephalometric measurements analyzed and the stages of calcification for either group

Estudo comparativo dos resultados oclusais e da eficiência dos protocolos de tratamento em uma e duas fases da má oclusão de Classe II, divisão 1

O objetivo deste estudo retrospectivo foi comparar os resultados oclusais e a eficiência dos protocolos de tratamento em uma e duas fases da má oclusão de Classe II, divisão 1. A eficiência do tratamento foi definida como um melhor resultado oclusal em um menor tempo de tratamento. Uma amostra de 139 pacientes com má oclusão de Classe II, divisão 1 foi dividida em dois grupos de acordo com o protocolo de tratamento instituído para a correção da má oclusão de Classe II: Grupo 1, constituído por 78 pacientes, tratados com o protocolo de tratamento em uma fase com idades médias inicial e final de 12,51 ('+ou-' 1,28) e 14,68 ('+ou-' 1,49) anos, respectivamente e Grupo 2, constituído por 61 pacientes, tratados com o protocolo de tratamento em duas fases com idades médias inicial e final de 11,21 ('+ou-' 1,21) e 14,70 ('+ou-' 1,55) anos, respectivamente. Telerradiografias em norma lateral foram obtidas ao início do tratamento para avaliar a compatibilidade cefalométrica dos grupos. Os resultados oclusais foram avaliados nos modelos de gesso dos pacientes nas fases inicial e final utilizando os índices PAR e IPT. Aplicou-se o teste do qui-quadrado para avaliar a compatibilidade dos grupos quanto à severidade da relação ântero-posterior dos arcos dentários e à distribuição por gêneros. As variáveis diretamente relacionadas aos resultados oclusais foram comparadas por meio do teste t independente. O coeficiente de correlação de Pearson foi calculado para avaliar a relação existente entre os índices PAR e IPT nas fases inicial e final do tratamento. Finalmente, uma análise de regressão foi realizada a fim de verificar a influência de diversas variáveis no tempo de tratamento. Verificou-se que resultados oclusais semelhantes são obtidos com os protocolos de tratamento em uma e duas fases, no entanto o tempo de tratamento foi significantemente menor no grupo tratado em uma fase. Baseado nos resultados deste trabalho deste trabalho pode-se concluir que o tratamento da má oclusão de Classe II, divisão 1 é mais eficiente quando realizado com o protocolo de tratamento em uma fase.The purpose of this study was to compare the dentoalveolar outcomes and the efficiency of 1-phase and 2-phase treatment protocols in Class II, division 1 malocclusions. Treatment efficiency was defined as a better dentoalveolar result in a shorter treatment time. Class II, division 1 subjects (n=139) were divided into two groups in agreement with the treatment protocol adopted for Class II correction. Group 1 comprised 78 patients treated with 1-phase treatment protocol (single-stage group) at initial and final mean ages of 12.51 ('+ou-' 1.28) and 14.68 ('+ou-' 1.49) years. Group 2 comprised 61 patients treated with 2-phase treatment protocol (two-stage group) at initial and final mean ages of 11.21 ('+ou-' 1.21) and 14.70 ('+ou-' 1.55) years. Lateral cephalometric radiographs were taken at the pretreatment stage to evaluate morphological differences among treatment groups. Evaluations were performed on the initial and final study models of the patients using the peer assessment rating (PAR) and treatment priority (TPI) indexes. Chi-square tests were used to compare the two groups regarding initial molar Class and gender distribution. Variables regarding occlusal results were compared using independent t-tests. Pearson correlation coefficients were calculated to examine relationships between PAR and TPI at initial and final stages. Finally, a regression analysis was completed, with total treatment time as the dependent variable to identify clinical factors that predict treatment length for patients with Class II malocclusions. Results demonstrated that similar dentoalveolar outcomes are obtained between 1-phase and 2-phase treatment protocols, but the duration of treatment was significantly smaller in the 1-phase treatment protocol group. Based on the results of this investigation, it can be concluded that treatment of Class II, division 1 malocclusions is more efficient with the 1-phase treatment protoco

Comparative study of the chronology of eruption of permanent teeth and calcification of second molars in Angle Class I and Class II malocclusions.

O objetivo deste estudo foi comparar a cronologia de erupção dos dentes permanentes e os estágios de calcificação dos segundos molares nas másoclusões de Classe I e Classe II de Angle e avaliar a existência de correlação entre esses estágios de calcificação e as grandezas cefalométricas SNA, SNB, ANB, Co-A e Co-Gn. Para avaliar a cronologia de erupção dos dentes permanentes (com exceção dos terceiros molares), foram utilizados 527 pares de modelos de gesso de jovens na faixa etária dos 5 aos 13 anos de idade que foram divididos em dois grupos. O grupo 1 ficou constituído por modelos de gesso que apresentassem uma relação molar de Classe I de Angle, e o grupo 2, por aqueles que apresentassem uma relação molar de Classe II de Angle. A idade média de erupção dos dentes permanentes foi determinada pelo método de Karber. A comparação entre os grupos foi realizada por meio do teste t independente. Para avaliar os estágios de calcificação dos segundos molares e a existência de correlação com as grandezas cefalométricas SNA, SNB, ANB, Co-A e Co-Gn, foram utilizadas 60 radiografias panorâmicas e 60 telerradiografias em norma lateral dos mesmos jovens, obtidas aos 8 anos de idade. Estas radiografias também foram divididas em dois grupos. O grupo 1 ficou constituído por radiografias de jovens com relação molar de Classe I de Angle e o grupo 2 por radiografias de jovens com relação molar de Classe II de , Angle. Os estágios de calcificação dos segundos molares foram determinados pelo método de NOLLA. A comparação entre os grupos foi realizada por meio do teste não paramétrico de Mann-Whitney. Os resultados mostraram que, de uma maneira geral, os indivíduos com relação molar de Classe I de Angle apresentam idades de erupção dos dentes permanentes mais precoces que os indivíduos com relação molar de Classe II de Angle, e esta diferença foi estatisticamente significante para todos os segundos molares, além dos dentes 15, 23, 34 e 45. Não houve diferença estatisticamente significante entre os estágios de calcificação dos segundos molares nos grupos considerados e não houve correlação entre as variáveis cefalométricas estudadas e os estágios de calcificação em nenhum dos grupos.The objective of this study was to compare the chronology of eruption of permanent teeth and the stages of calcification of the second molars in Angle Class I and Class II malocclusions, as well as to investigate if there is any correlation between these stages of calcification and the cephalometric measurements SNA, SNB, ANB, Co-A, Co-Gn. For evaluation of the chronology of eruption of permanent teeth (except for the third molars), 527 pairs of dental casts of young subjects aged 5 to 13 years old were employed, which were divided in two groups. Group 1 comprised dental casts presenting Angle Class I molar relationship, whereas Group 2 included those displaying an Angle Class II molar relationship. The mean age of eruption of the permanent teeth was determined by means of the Karbers method. Comparison between groups was evaluated by the independent t test. For evaluation of the stages of calcification of the second molars and presence of correlation with the cephalometric measurements SNA, SNB, ANB, Co-A, Co-Gn, 60 panoramic radiographs and 60 lateral cephalograms of the same subjects were used, which had been obtained at 8 years old. These radiographs were also divided in two groups. Group 1 comprised radiographs of young individuals presenting Class I molar relationship, and Group 2 involved subjects with Class II molar relationship. The stages of calcification of the second molars were determined as suggested by Nolla. Comparison between groups was accomplished through the nonparametric Mann-Whitneys test. The results demonstrated that, in general, individuals presenting Class I molar relationship presented earlier mean ages of eruption of the permanent teeth when compared to those subjects with Class II molar relationship. This difference was statistically significant for all second molars, as well as for the teeth 15, 23, 34 and 45. No statistically significant differences could be found between the stages of calcification of the second molars in the evaluated groups; moreover, there was no correlation between the cephalometric measurements analyzed and the stages of calcification for either group