Influência da Temperatura Pré-Polimerização e do Tempo de Fotoativação na Microinfiltração Marginal
Influence of pre-cure temperature and photo-activation time in the marginal microleakage
Torres, A.C.M.; Torres, C.R.G.; Araújo, M.A.M.
Rev. odontol. UNESP, vol.33, n4, p.163-168, 2004
Resumo
O objetivo deste estudo foi avaliar a influência da temperatura pré-polimerização e do tempo de fotoativação da resina composta na microinfiltração marginal. Para tal, 60 incisivos bovinos receberam preparos classe V na junção amelo-cementária e aplicação do sistema adesivo Prime & Bond NT (Dentsply), sendo restaurados com incremento único de Z250 (3M). Eles foram divididos em seis grupos de acordo com a temperatura e o tempo de fotoativação: G1 - o compósito foi resfriado a 5°C e fotoativado por 20 s; G2 - 5°C/40 s; G3 - o compósito foi mantido a temperatura ambiente de 24°C e fotoativado por 20 s; G4 - 24°C/40 s; G5 - o compósito foi aquecido a 54°C e fotoativado por 20 s; G6 - 54°C/40 s. Os dentes restaurados foram imersos em água destilada a 37°C por 24 horas e posteriormente receberam acabamento, polimento e 500 ciclos térmicos (5 e 55°C). A microinfiltração foi avaliada quantitativamente em milÃmetros pelo método do nitrato de prata seguido pela diafanização. Os dados foram submetidos a ANOVA paramétrica e teste de Tukey (α = 5%), obtendo-se um valor de p = 0,00. As médias (± desvio padrão) observadas para cada grupo foram: G6:1,7(± 1,0)a; G2:2,7(± 1,3)ab; G1:2,7(± 1,6)ab; G5:3,1(± 1,0)abc; G3:3,8(± 1,0)bc; G4:4,3(± 0,3)c. Os grupos acompanhados das mesmas letras não apresentam diferenças significantes. Pôde-se concluir que, utilizando 40 segundos de fotoativação, o aquecimento reduziu significativamente a microinfiltração em relação à temperatura ambiente, enquanto o resfriamento não produziu efeitos significantes. Utilizando 20 segundos de fotoativação, a variação de temperatura não exerceu efeitos significativos.
Palavras-chave
Infiltração dentária, resina composta, temperatura ambiente
Abstract
The aim of this study was to evaluate the influence of pre-cure temperature and photo-activation time in the microleakage of composite resin restorations. For such, 60 bovine incisor received class V preparations in the CEJ and application of the adhesive system Prime & Bond NT (Dentsply), being restored with a bulk increment of Z250 (3M). They were divided in six groups in agreement with the temperature and the time of photo-activation: G1 - the composite was cooled to 5°C and photo-activated by 20 s; G2 - 5°C/40 s; G3 - the composite was maintained to room temperature of 24°C and photo-activated by 20 s; G4 - 24°C/40 s; G5 - the composite was heated up to 54°C and photo-activated by 20 s; G6 - 54°C/40 s. The restored teeth were immersed in distilled water at 37°C/24 h and later they received the finish, polishing and 500 thermal cycles (5 and 55°C). The microleakage was evaluated quantitatively in mm by the silver nitrate method followed by clearing technique. The data were submitted to parametric ANOVA and Tukey´s test (a = 5%), being obtained a p value of 0,00. The mean (± Standard Dev) observed for each group were: G6:1,7(± 1,0)a; G2:2,7(± 1,3)ab; G1:2,7(± 1,6)ab; G5:3,1(± 1,0)abc; G3:3,8(± 1,0)bc; G4:4,3(± 0,3)c. Groups with same letters were no statistically different.We can conclude that using 40 s of photo-activation, the heating reduced significantly the microleakage in relation to room temperature, while the cooling didn’t produce significant effects. Using 20 s of photo-activation, the temperature variation didn’t showed significant effects.
Keywords
Dental leakage, composite resin, temperature
Referências
1. Anusavice KJ. Phillips materiais dentários. Rio de Janeiro: Guanabara Koogan; 1998.
2. Barghi N, Berry T, Hatton C. Evaluating intensity output of curing lights in private dental offices. J Am Dent Assoc. 1994; 125: 992-6.
3. Bausch JR, de Lange K, Davidson CL, Peters A, de Gee AJ. Clinical significance of polymerization shinkage of composite resins. J Prosthet Dent. 1982; 48: 59-67.
4. Bergenholtz G, Cox CF, Loesche WJ, Syed SA. Bacterial leakage aroud dental restorations: its effects on the dental pulp. J Oral Pathol. 1982; 11: 439-50.
5. Chuang SF, Liu JK, Jin YT. Microleakage and internal voids in class II composite restoration with flowable composite linings. Oper Dent. 2001; 26: 193-200.
6. Davidson CL, De Gee AJ, Feilzer A. A competition between the composite-dentin bond strength and the polymerization contraction stress. J Dent Res. 1984; 63: 1396-9.
7. Dickinson GL, Leinfelder K. Assessing the long-term effect of surface penetranting sealant. J Am Dent Assoc. 1993; 124: 68-72.
8. Friedman J. Thermally assisted flow and polymerization of composite resins. Contemp Esthet Rest Pract. 2003; 7: 46.
9. Hansen EK, Asmussen E. Visible-light curing units: correlation between depth and distance between exit window and resin surface. Acta Odontol Scand. 1997; 55: 162-6.
10. Hussey DL, Biagioni PA, Lamey PJ. Thermographic measurement of temperature change during resin composite polymerization in vivo. J Dent. 1995; 23: 267-71.
11. Littlejohn L, Creer SC, Pucket AD, Fitchie J. Curing efficiency of a direct composite at differents temperatures. In: 32nd Annual Meeting and Exhibition of the AADR; 2003 March 12-15; San Antonio. Texas:AADR; 2003. p. 944.
12. Loney RW, Price RBT. Temperature transmission of high-output light-curing units through dentin. Oper Dent. 2001; 26: 516-20.
13. Pashley DH. Clinical considerations of microleakage. J Endod. 1990; 16: 70-7.
14. Pereira SK, Porto CLA, Mendes AJD. Avaliação da dureza superficial de uma resina composta hÃbrida em função da cor, tempo de exposição, intensidade de luz e profundidade do material. J Bras Clin Estet Odontol. 2000; 4: 63-7.
15. Santos LA. Microdureza de resina composta: efeito de aparelhos e tempos de polimerização em diferentes profundidades. Pesqui Odontol Bras. 2000; 14: 65-70.
16. Sobrinho LC, de Lima AA, Consani S, Sinhoreti MA, Knowles JC. Influence of curing tip distance on composite knoop hardness values. Braz Dent J. 2000; 11: 11-7.
17. Tay FR, Pang KM, Gwinnett AJ, Wei SH. A method for microleakage evaluation along the dentin/restoretive interface. Am J Dent. 1995; 8: 105-8.
18. Torres CRG, Araújo MAM, Torres ACM. Effects of dentin collagen removal on microleakage of bonded restorations. J Adhes Dent. 2004; 6: 33-42.
19. Trujillo M, Stansbury JW. Thermal effects on composite photopolymerization monitored by real-time NIR. In: 32nd Annual Meeting and Exhibition of the AADR; 2003 March 12-15; San Antonio. Texas: AADR; 2003. p. 891.
20. Vicentini A. Fotopolimerização das resinas compostas. RGO. 1996; 44: 146-8.
21. Vogel K, Rueggeberg F, Rheinberger V. Influence of initiator system and temperature on real time double bond conversion. In: 32nd Annual Meeting and Exhibition of the AADR; 2003 March 12-15; San Antonio. Texas: AADR; 2003. p.820.
22. Yap AU, Seneviratne C. Influence of light energy density on effectiveness of composite cure. Oper Dent. 2001; 26: 460-6.
23. Zach L, Cohen G. Pulp response to externally applied heat. Oral Surg Oral Med Oral Pathol. 1965; 19: 515-30
Facebook
Google+
Twitter
LinkedIn
Mendeley
StumbleUpon
CiteULike
Reddit
Email