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Previous issue date: 2008-04-11 / The aim of the present study was to assess the effectiveness and adverse effects on dental enamel caused by nightguard vital bleaching with 10% carbamide peroxide. This was accomplished through the interaction of researchers from different areas such as dentistry, materials engineering and physics. Fifty volunteers took part in the doubleblind
randomized controlled clinical trial. They were allocated to an experimental group that used Opalescence PF 10% (OPA) and a control group that used a placebo gel (PLA). Fragments of human dental enamel from the vestibular surface of healthy
premolars, extracted for orthodontic reasons, were fixed to the vestibular surface of the first upper molars of the volunteers for in situ observation. Bleaching was performed at
night for 21 days. The observation periods included Baseline (BL), T0 (21 days), T30 (30 days after treatment) and T180 (180 days after treatment, only for the OPA group).
Tooth color was assessed by comparing it with the Vita? scale and by the degree of satisfaction expressed by the volunteer. We also assessed adverse clinical effects,
dental sensitivity and gingival bleeding. The study of adverse effects on enamel was conducted in vivo and in situ, using the DIAGNOdent? laser fluorescence device to detect mineral loss. Scanning electron microscopy (SEM) was used to check for superficial morphological alterations, energy dispersive spectrophotometry (EDS) to semiquantitatively assess chemical composition using the Ca/P ratio, and the x-ray
diffraction (XRD) technique to observe alterations in enamel microstructure. The results showed that nightguard vital bleaching with 10% carbamide peroxide was effective in
96% of the cases, versus 8% for the PLA group. Dental sensitivity was present in 36% (9/25) of the cases. There was no significant association between gingival bleeding and
the type of gel used (p = 1.00). In vivo laser fluorescence analysis showed no difference in values for the control group, whereas in the OPA group there was a statistically
significant difference between baseline values in relation to the subsequent periods (p<0.01), with lower mean values for post-bleaching times. There was a significant difference between the groups for times T0 and T30. Micrographic analysis showed no enamel surface alterations related to the treatment performed. No significant alteration in Ca/P ratio was observed in the OPA group (p = 0.624) or in the PLA group (p = 0.462) for each of the observation periods, nor between the groups studied (p=0.102). The XRD pattern for both groups showed the presence of three-phase Hydroxyapatite according to JCPDS files (9-0432[Ca5(PO4)3(OH)], 18-0303[Ca3(PO4)2.xH2O] and 25-0166[Ca5(PO4)3(OH, Cl, F)]). No other peak associated to other phases was found, independent of the group analyzed, which reveals there was no disappearance, nucleation or phase transformation. Neither was there any alteration in peak pattern location. With the methodology and protocol used in this study, nightguard vital bleaching with 10% carbamide peroxide proved to be an effective and safe procedure
for dental enamel / O presente estudo objetivou avaliar a efetividade e os efeitos adversos sobre o esmalte dent?rio promovidos pelo clareamento caseiro supervisionado pelo dentista com
per?xido de carbamida a 10% e s? foi poss?vel mediante a intera??o de alguns pesquisadores das mais variadas ?reas do conhecimento como a Odontologia, a Engenharia de Materiais e a F?sica. Cinq?enta volunt?rios participaram de um ensaio
cl?nico controlado e randomizado duplo-cego e foram alocados em um grupo experimental, que utilizou Opalescence PF 10% (OPA) e um grupo controle que usou um gel placebo (PLA). Fragmentos de esmalte dent?rio humano provenientes da face
vestibular de pr?-molares h?gidos, extra?dos por motivos ortod?nticos, foram fixados ? superf?cie vestibular dos primeiros molares superiores dos volunt?rios objetivando uma
observa??o in situ. O tempo do clareamento foi de 21 dias em regime noturno. Os per?odos de observa??o compreenderam a Linha Base (LB), T0 (21 dias), T30 (30 dias ap?s o tratamento) e T180 (180 dias ap?s o tratamento) sendo este ?ltimo apenas para o grupo OPA. A avalia??o da cor dos dentes foi feita pela compara??o com a escala Vita? e atrav?s do grau de satisfa??o do volunt?rio em rela??o ao tratamento. Adicionalmente, avaliaram-se os efeitos cl?nicos adversos, sensibilidade dent?ria e sangramento gengival. O estudo dos efeitos adversos ao esmalte dent?rio foi realizado
in vivo e in situ, atrav?s da fluoresc?ncia a laser com o uso do DIAGNOdent?, objetivando detectar perdas de mineral. Foram empregadas ainda, a Microscopia Eletr?nica de Varredura (MEV), para verificar altera??es morfol?gicas superficiais, a Espectrometria de Energia Dispersiva (EDS), para avaliar semiquantitativamente a composi??o qu?mica atrav?s do ratio Ca/P, e a t?cnica de Difra??o de Raio-X (DRX)
com a finalidade de observar altera??es na microestrutura do esmalte. Os resultados revelaram ser a t?cnica de clareamento caseiro com per?xido de carbamida a 10%
efetiva em 96% dos casos, contra 8% do grupo PLA, apresentando 36% (9/25) de sensibilidade dent?ria. N?o houve associa??o significativa entre a presen?a de
sangramento gengival e o tipo de gel utilizado (p=1,00). A an?lise da fluoresc?ncia a laser in vivo n?o revelou diferen?a nos valores para o grupo controle, enquanto no grupo OPA houve diferen?a estatisticamente significativa entre os valores da linha base em rela??o aos per?odos subseq?entes (p<0,01), com valores m?dios menores nos tempos p?s-clareamento. Entre os grupos, houve diferen?a significativa nos per?odos T0 e T30. A avalia??o das micrografias n?o revelou altera??es na superf?cie do esmalte que possam ser relacionadas ao tratamento realizado. Nenhuma altera??o significativa na propor??o Ca/P foi observada no grupo OPA (p=0,624) nem no grupo PLA (p=0,462) para cada um dos per?odos de observa??o, nem entre os grupos estudados (p=0,102). O padr?o da DRX para todos os grupos evidenciou a presen?a de tr?s fases relativas ? hidroxiapatita de acordo com os arquivos JCPDS (9-0432[Ca5(PO4)3(OH)], 18-
0303[Ca3(PO4)2.xH2O] e 25-0166[Ca5(PO4)3(OH,Cl,F)]). Nenhum outro pico associado a outras fases foi encontrado, independente do grupo analisado, o que revela n?o ter
havido desaparecimento, nuclea??o ou transforma??o de fases. Pode-se constatar ainda que n?o houve altera??o no padr?o dos picos em rela??o ? localiza??o dos mesmos. Atrav?s da metodologia empregada neste estudo, pode-se concluir que o clareamento caseiro supervisionado pelo dentista com per?xido de carbamida a 10%, dentro do protocolo aqui utilizado, se mostrou um procedimento efetivo e seguro para o esmalte dent?rio
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/13141 |
| Date | 11 April 2008 |
| Creators | Medeiros, Maria Cristina dos Santos |
| Contributors | CPF:50337157472, http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4723244A9, Montes, Marcos Antonio Japiass? Resende, CPF:40841650420, http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4730769Z6, Santos, Alex Jos? Souza dos, CPF:02495093698, http://lattes.cnpq.br/4467371801832022, Alves J?nior, Clodomiro, CPF:09621199468, http://lattes.cnpq.br/7441669258580942, Costa, Ant?nio de Lisboa Lopes, CPF:32381611487, http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4786083Z7&dataRevisao=null, Lima, Kenio Costa de |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Ci?ncias da Sa?de, UFRN, BR, Ci?ncias da Sa?de |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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