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1.
JDR Clin Trans Res ; 2(2): 132-141, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28435894

RESUMO

The objective of this cross-sectional study was to clinically validate an array of biochemical tests for oral acid/alkali generation as caries screening instruments. 185 adult subjects (mean 33.6±10.6 years) were examined clinically for dental caries using the ICDAS criteria. Bitewing radiographs were used to confirm interproximal surfaces of posterior teeth. For the purposes of this study, subjects were classified as "caries-active" if they had at least one untreated caries lesion with ICDAS 4 or higher. Pooled supragingival plaque and unstimulated saliva samples were collected and assayed for pH changes from sucrose and urea metabolism using colorimetric tests. The validity of each test to discriminate between "caries-inactive" and "caries-active" subjects was assessed and compared to a commercial bacteriological caries-screening test using roc regression and logistic regression models. The AUCs of the plaque-urea (PU: 0.59 (0.51, 0.67)), plaque-urea-glucose (PUG: 0.59 (0.51, 0.67)) and saliva-urea-glucose (SUG: 0.59 (0.51, 0.67)) tests did not differ significantly from the bacteriological tests (CRT-mutans: 0.62 (0.54, 0.70); CRT-lactobacillus: 0.63 (0.56, 0.71) (P>0.05), but the plaque-glucose (SG), saliva-glucose (SG), saliva-urea (SU) and saliva-plaque-glucose (SPG) tests had significantly smaller AUCs (P<0.05). The AUCs for the PU, PUG, SUG, and the CRT-mutans tests were higher in subjects who had no existing dental restorations (PU: 0.90 (0.77, 1.04); PUG: 0.90 (0.79, 1.01); SUG: 0.89 (0.69, 1.08); CRT-mutans: 0.90 (0.73, 1.08)). The incorporation of the biochemical tests into a multidimensional bacteriological/psychosocial caries screening model significantly increased its diagnostic values (Se+Sp: 160.6, AUC: 0.846). In conclusion, as a proof of concept, the results of this study indicate that measuring the ability of dental plaque and saliva to metabolize urea together with the ability to generate acid from sugars may have a promising role in caries screening either independently, or as part of a multidimensional biological test.

2.
Arch Oral Biol ; 56(12): 1560-8, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21784411

RESUMO

UNLABELLED: Recent cross-sectional studies suggest that reduced ability to generate alkali via the urease pathway in dental plaque may be an important caries risk factor, but it has not been assessed prospectively. OBJECTIVE: To evaluate the effect of plaque and saliva urease activity on the risk for developing new caries over a three-year period in children. METHODS: A panel of 80 children, three to six years of age at recruitment, was followed prospectively for three years. Plaque urease activity, saliva urease activity and dental caries were measured every six months. Survival analysis methodology was used to evaluate the effect of urease on caries development during the study period adjusted for gender, age, baseline caries levels, sugar consumption, amount of plaque, and mutans streptococci levels. RESULTS: The risk for developing new caries increased in a dose-responsive manner with increasing levels of urease activity in saliva (adjusted HR(Q4 vs. Q1): 4.98; 95% CI: 1.33, 18.69) and with decreasing urease activity in plaque (adjusted HR(Q4 vs. Q1): 0.29; 95% CI: 0.11, 0.76). Multiple measurements of urease activity were conducted to overcome the variability of urease activity in this study. Baseline caries and mutans streptococci in saliva were also important predictors of caries risk. CONCLUSIONS: Increased urease activity in saliva can be an indicator of increased caries risk in children, whilst increased urease activity in plaque may be associated with reduced caries risk. The reproducibility of urease measurements must be improved before these findings can be further tested and clinically applied.


Assuntos
Cárie Dentária/enzimologia , Placa Dentária/química , Saliva/química , Urease/análise , Carboidratos/administração & dosagem , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Modelos de Riscos Proporcionais , Estudos Prospectivos , Reprodutibilidade dos Testes , Medição de Risco , Fatores de Risco , Streptococcus mutans/isolamento & purificação , Análise de Sobrevida
3.
Arch Oral Biol ; 56(11): 1282-9, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21616477

RESUMO

UNLABELLED: Bacterial urease activity in dental plaque and in saliva generates ammonia, which can increase the plaque pH and can protect acid-sensitive oral bacteria. Recent cross-sectional studies suggest that reduced ability to generate ammonia from urea in dental plaque can be an important caries risk factor. In spite of this proposed important clinical role, there is currently no information available regarding important clinical aspects of oral ureolysis in children. OBJECTIVE: The objective of this study was to evaluate the distribution and pattern of urease activity in the dental plaque and in the saliva of children during a three-year period, and to examine the relationship of urease with some important caries risk factors. METHODS: A longitudinal study was conducted with repeated measures over a three-year period on a panel of 80 children, aged 3-6 years at recruitment. The dynamics of change in urease activity were described and associated with clinical, biological, and behavioural caries risk factors. RESULTS: Urease activity in plaque showed a trend to remain stable during the study period and was negatively associated with sugar consumption (P<0.05). Urease activity in unstimulated saliva increased with age, and it was positively associated with the levels of mutans streptococci in saliva and with the educational level of the parents (P<0.05). CONCLUSIONS: The results of this study reveal interesting and complex interactions between oral urease activity and some important caries risk factors. Urease activity in saliva could be an indicator of mutans infection in children.


Assuntos
Placa Dentária/enzimologia , Saliva/enzimologia , Saliva/microbiologia , Streptococcus mutans/enzimologia , Urease/metabolismo , Biofilmes , Criança , Pré-Escolar , Índice CPO , Cárie Dentária/etiologia , Sacarose Alimentar , Escolaridade , Feminino , Humanos , Concentração de Íons de Hidrogênio , Funções Verossimilhança , Modelos Lineares , Masculino , Pais , Estudos Prospectivos , Fatores de Risco , Estatísticas não Paramétricas
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