RESUMEN
OBJECTIVE: This study evaluated the force system generated by the Memory Titanol® spring (MTS) with different preactivation bends using an orthodontic force tester (OFT). METHODS: Three preactivations were tested using a 0.017 × 0.022-in stainless steel (SS) wire and a 0.018 × 0.025-in NiTi segment, with an activation of 30º in the posterior segment (ß), with 0º (Group 1 [G1]), 45º (Group 2 [G2]), and 60º (Group 3 [G3]) in the anterior segment (α). RESULTS: The molars showed extrusion values of -1.33 N for G1 and -0.78 N for G2, and an intrusion value of 0.33 N for G3. The force in the premolars was intrusive with a variation of 1.34 N for G1 and 0.77 N for G2; and extrusive with a variation of -0.31 N for G3. Regarding the upright moment (Ty) of the molar, a distal moment was observed with values of 53.45 N.mm for G1 and 19.87 N.mm for G2, while G3 presented a mesial moment of -6.23 N.mm. G1, G2, and G3 all exhibited distal premolar moments (Ty) of 3.58, 2.45, and 0.68 N.mm, respectively. CONCLUSIONS: The tested preactivations exerted an extrusive force in G1 and G2 and an intrusive force in G3 during molar vertical movement. The premolar region in G1 and G2 showed intrusive force and distal moment.
Asunto(s)
Alambres para Ortodoncia , Acero Inoxidable , Titanio , Técnicas de Movimiento Dental , Acero Inoxidable/química , Técnicas de Movimiento Dental/instrumentación , Titanio/química , Humanos , Diseño de Aparato Ortodóncico , Análisis del Estrés Dental , Ensayo de Materiales , Diente Premolar , Níquel/química , Aleaciones Dentales/química , Diente Molar , Estrés MecánicoRESUMEN
OBJECTIVE: This descriptive observational study aimed to determine clinically relevant and applicable data of enamel thickness (ETH), considering the mesio-distal differences of anterior and posterior permanent teeth and their relationships. MATERIAL AND METHODS: The sample consisted of right-sided standardized radiographs of 34 individuals (21 females and 13 males), aged between 13 and 24 (average 16) years, with all permanent teeth intact and without crowding. Four periapical and four interproximal radiographs were obtained and digitized. ETH measurements (mesial to distal contact points at the dentin-enamel junction) were performed after correction for radiographic image magnification. The Students' t-test was applied to the differences between paired means, with the Pearson correlation to evaluate the correlation between them. RESULTS: The mesial and distal ETH increased from the anterior to the posterior teeth. Incisor ETH ranged between 0.60 and 0.84 mm. Canines, premolars, and molars were more than 1.0 mm thick, and molar enamel reached values between 1.26 and 1.44 mm. CONCLUSION: Distal ETH was significantly greater than the mesial ETH, and progressively thicker from the anterior to posterior teeth. Interproximal reduction (IPR) of the lower central and upper lateral incisors should be avoided, reduced, or performed on their distal surfaces. There is a positive and significant correlation between ETH and the mesial and distal surfaces of the teeth. Periapical radiographs and evaluation of the remaining ETH are necessary in cases of retreatment. The location and number of tooth size discrepancies should be considered in treatment planning and appropriately compensated with IPR.
Asunto(s)
Esmalte Dental , Dentición Permanente , Humanos , Femenino , Esmalte Dental/diagnóstico por imagen , Esmalte Dental/anatomía & histología , Masculino , Adolescente , Adulto Joven , Diente Premolar/diagnóstico por imagen , Diente Premolar/anatomía & histología , Diente Molar/diagnóstico por imagen , Diente Molar/anatomía & histología , Incisivo/diagnóstico por imagen , Incisivo/anatomía & histología , Diente Canino/diagnóstico por imagen , Diente Canino/anatomía & histologíaRESUMEN
ABSTRACT Objective: This descriptive observational study aimed to determine clinically relevant and applicable data of enamel thickness (ETH), considering the mesio-distal differences of anterior and posterior permanent teeth and their relationships. Material and Methods: The sample consisted of right-sided standardized radiographs of 34 individuals (21 females and 13 males), aged between 13 and 24 (average 16) years, with all permanent teeth intact and without crowding. Four periapical and four interproximal radiographs were obtained and digitized. ETH measurements (mesial to distal contact points at the dentin-enamel junction) were performed after correction for radiographic image magnification. The Students' t-test was applied to the differences between paired means, with the Pearson correlation to evaluate the correlation between them. Results: The mesial and distal ETH increased from the anterior to the posterior teeth. Incisor ETH ranged between 0.60 and 0.84 mm. Canines, premolars, and molars were more than 1.0 mm thick, and molar enamel reached values between 1.26 and 1.44 mm. Conclusion: Distal ETH was significantly greater than the mesial ETH, and progressively thicker from the anterior to posterior teeth. Interproximal reduction (IPR) of the lower central and upper lateral incisors should be avoided, reduced, or performed on their distal surfaces. There is a positive and significant correlation between ETH and the mesial and distal surfaces of the teeth. Periapical radiographs and evaluation of the remaining ETH are necessary in cases of retreatment. The location and number of tooth size discrepancies should be considered in treatment planning and appropriately compensated with IPR.
RESUMO Objetivo: Este estudo observacional descritivo teve como objetivo determinar dados clinicamente relevantes e aplicáveis da espessura do esmalte (EES), considerando as diferenças mésiodistais dos dentes anteriores e posteriores e suas relações. Material e Métodos: A amostra consistiu em radiografias periapicais padronizadas do lado direito de 34 indivíduos, 21 do sexo feminino e 13 do sexo masculino, com idade entre 13 e 24 anos (média = 16 anos), com todos os dentes permanentes íntegros e sem apinhamento. Quatro radiografias periapicais e quatro radiografias interproximais foram tiradas e digitalizadas. As medidas de EES (dos pontos de contato mesial e distal até a junção dentina-esmalte) foram realizadas após correção para adequar a ampliação da imagem radiográfica. Para as diferenças entre as médias pareadas, foi aplicado o teste t de Student com correlação de Pearson, para avaliar a correlação entre elas. Resultados: A EES mesial e distal aumenta dos dentes anteriores para os posteriores. A EES dos incisivos variou entre 0,6 e 0,84 mm. Caninos, pré-molares e molares apresentaram EES superior a 1,0 mm e a EES dos molares atingiu valores entre 1,26 e 1,44 mm. Conclusão: As EES distais são significativamente maiores que as mesiais e progressivamente mais espessas dos dentes anteriores para posteriores. A redução interproximal do esmalte (RIP) dos incisivos centrais inferiores e laterais superiores deve ser evitada, minimizada ou realizada em suas superfícies distais. Radiografias periapicais e avaliação da EES remanescente são necessárias nos casos de retratamento. A localização e o número de discrepâncias no tamanho dos dentes devem ser determinados e considerados no planejamento do tratamento, para que sejam adequadamente compensados durante o tratamento com RIP.