Detection of oral bacterial DNA in synovial fluid.

OBJECTIVES: As periodontal bacteria might be involved in the aetiology of rheumatic diseases, we analysed synovial fluid obtained from patients with rheumatoid arthritis (RA) and controls for the presence of DNA of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, and Treponema denticola. METHODS: In all, 42 patients suffering from RA (mean age 53.8 ± 16.7 years, 40.4% females) and 114 controls with no rheumatic diseases (mean age 56.1 ± 15.2 years, 52.4% females) were included. DNA from synovial fluid was isolated by QiaAmp kit (Qiagen, Hilden, Germany). Polymerase chain reactions (PCRs) specific for the 16S rRNA genes of the above specified bacteria were developed. Subgingival bacterial colonization was analysed using micro-Ident(®) test (HAIN-Diagnostik, Nehren, Germany). RESULTS: In patients with RA DNA of P. gingivalis was detected in synovial fluid more often than in controls (15.7% versus 3.5%, p = 0.045). More patients than controls harboured DNA from P. gingivalis in both, oral plaque and synovial fluid (11.9% versus. 0.9%, p = 0.030). Among the patients group the number of missing teeth was correlated with the number of joints with movement restrictions caused by RA. CONCLUSIONS: DNA of periodontopathogens can be found in synovial fluid and oral bacteria may play a role in the pathogenesis of arthritis.

The influence of application of different desensitisers on root dentine demineralisation in situ.

AIM: To evaluate the influence of three desensitisers on root caries demineralisation in situ. METHODS: The root surfaces of 36 freshly extracted human molars were used to prepare root dentine specimens. These specimens were distributed among the following groups: A: Admira Protect, V: VivaSens, H: Hyposen, C: control group, untreated. Two dentine specimens of each group were inserted into two buccal aspects of intraoral mandibular appliances. The appliances were worn by nine persons for five weeks, day and night. One side was brushed daily with a toothpaste. On the other side, plaque was allowed to grow. Individual oral hygiene techniques were performed without any fluorides. After the in situ period, two slabs were ground. The depth of the demineralised areas was determined using a polarised light microscope. RESULTS: ANOVA revealed significant differences between brushed and non-brushed specimens. Lesion depths in the brushed group were significantly decreased (p < 0.05, Tukey's test). CONCLUSIONS: Within the limitations of an in situ study it can be concluded that the demineralisation of the root surface can be hampered by application of desensitisers under different oral hygiene conditions. The application of clinical proven desensitising agents might have a caries-protective effect on exposed root surfaces.

Apical sealing ability of 2 epoxy resin-based sealers used with root canal obturation techniques based on warm gutta-percha compared to cold lateral condensation.

OBJECTIVE: To evaluate the apical sealing ability of 2 epoxy resin-based root canal sealers used with 2 different warm gutta-percha obturation techniques and cold lateral condensation. METHOD AND MATERIALS: The root canals of 72 freshly extracted single-root incisors were prepared and randomly assigned to 6 experimental groups. Root canal fillings were performed using either cold lateral condensation, warm vertical condensation, or Thermafil obturators with EndoRez or AH Plus as sealer. After root canal filling, the teeth were stored in 5% methylene blue solution for 7 days. Linear dye penetration was measured in bisected specimens by a calibrated investigator using a light microscope. RESULTS: Statistical analysis revealed significantly higher penetration depths in groups where EndoRez was used (P < .05, Tukey test). Regarding the different obturation techniques, the least amount of dye penetration was observed for AH Plus and EndoRez when warm vertical condensation was used. CONCLUSION: The results of this study indicate that the apical sealing ability of EndoRez is not as effective as that of AH Plus. Thermafil obturators and warm vertical condensation achieved seals with low dye penetration depth. The use of these techniques might decrease the risk of apical leakage.

Influence of three different sealants on root dentin demineralization in situ.

PURPOSE: To evaluate in situ the onset of initial demineralization in human dentin pretreated either with two different dentin bonding agents or a desensitizer. METHODS: 28 freshly extracted human molars were included in this study. The root surfaces were thoroughly cleaned, thereby removing the cementum. From each tooth four root dentin specimens were prepared. The specimens were distributed among the following experimental groups: C: control group (untreated), S: Syntac Classic, X: Xeno III, and H: Hyposen. For each subject, one dentin specimen of each group was inserted into both buccal aspects of a bilateral intraoral mandibular appliance. The appliances were worn by 14 subjects for 5 weeks day and night. One side was brushed daily with fluoride-containing toothpaste (Aronal) (B). On the other side, plaque was allowed to grow (NB). Individual oral hygiene techniques were performed without any fluorides. During meals, the appliance was stored in 10% sucrose solution. After the in situ period, slabs (150 microm) were ground and studied using polarized light microscopy. RESULTS: For lesion depth, ANOVA revealed significant differences between brushed and unbrushed specimens. In the brushed groups, the following lesion depths were evaluated (mean values and standard deviation in microns): Group B-C: 74.1 (+/- 18.5), Group B-S: 27.6 (+/- 9.6); Group B-X: 28.7 (+/- 9.6), and Group B-H: 34.3 (+/- 20.6). The non-brushed specimens showed following lesion depths: Group NB-C: 101.7 (+/- 23.9), Group NB-S: 59.9 (+/- 13.1), Group NB-X: 52.5 (+/- 12.1), and Group NB-H: 72.9 (+/- 19.9). Compared to the non-brushed groups, lesion depths in the brushed group were significantly decreased (P < 0.05, Tukey's test). The reduction of lesion depths after application of the three agents was significant in both cases (brushed and non-brushed groups). Within the limitations of an in situ study it can be concluded that the demineralization of the root surface can be inhibited by application of dentin adhesives and desensitizers under different oral hygiene conditions.

Effect of tumor therapeutic irradiation on the mechanical properties of teeth tissue.

Tumor irradiation of the head-neck area is accompanied by the development of a so-called radiation caries in the treated patients. In spite of conservative therapeutic measures, the process results in tooth destruction. The present study investigated the effects of irradiation on the demineralization and remineralization of the dental tissue. For this purpose, retained third molars were prepared and assigned either to a test group, which was exposed to fractional irradiation up to 60 Gy, or to a non-irradiated control group. Irradiated and non-irradiated teeth were then demineralized using acidic hydroxyl-cellulose gel; afterwards the teeth were remineralized using either Bifluorid12 or elmex gelee. The nanoindentation technique was used to measure the mechanical properties, hardness and elasticity, of the teeth in each of the conditions. The values were compared to the non-irradiated control group. Irradiation decreased dramatically the mechanical parameters of enamel and dentine. In nonirradiated teeth, demineralization had nearly the same effects of irradiation on the mechanical properties. In irradiated teeth, the effects of demineralization were negligible in comparison to non-irradiated teeth. Remineralization with Bifluorid12 or elmex gelee led to a partial improvement of the mechanical properties of the teeth. The enamel was more positively affected by remineralization than the dentine.

The influence of human plasma used for in vitro dentin perfusion on microtensile bond strength of 5 self-conditioning dentin adhesives.

OBJECTIVE: The aim of this in vitro study was to evaluate the effect of human plasma, compared to physiologic saline, on microtensile bond strengths of 5 self-conditioning dentin adhesives when used as a dentin perfusion medium. METHOD AND MATERIALS: One hundred and fifty extracted human third molars were prepared in a special manner allowing the simulation of intrapulpal pressure and dentin perfusion. The specimens were randomly divided into 10 experimental groups. Five groups were perfused with physiologic saline, while the others were perfused with diluted human plasma, each under constant hydrostatic pressure of 30 cm H2O. One saline group and 1 human plasma group was then assigned to each of the following dentin adhesives: Clearfil SE Bond (Kuraray), Clearfil Protect Bond (Kuraray), Xeno 3 (Dentsply), Futurabond NR (Voco), and iBond (Heraeus Kulzer). The microtensile bond strength for each group was evaluated using a Zwick universal testing machine 10 minutes after light curing. RESULTS: Pairwise comparison showed a significant increase of bond strength in all human plasma-perfused subgroups (P < .05, Tukey's test). The influence of the different dentin adhesives was significant (P < .001, analysis of variance). The highest significant values were observed for Futurabond NR and iBond with human plasma (P < .05, closed test procedure). CONCLUSION: The use of human plasma might be a suitable alternative to imitate perfused dentin conditions in testing devices and might eliminate the discrepancy between different in vitro investigations focusing on bond strength of dentin adhesives.

The influence of human plasma used for dentin perfusion on tensile bond strength of different light-curing materials.

PURPOSE: To evaluate the influence of two perfusion solutions, saline and human plasma, on tensile bond strengths of five different light-curing materials in an in vitro investigation. METHODS: 150 human third molars were used. All teeth were prepared in a special manner allowing the simulation of intrapulpal pressure and dentin perfusion. Dentin specimens with a thickness of 3.5 mm were obtained under standardized conditions. The specimens were randomly assigned to 10 experimental groups. Five groups were perfused with physiologic saline while with the other five with human plasma under constant hydrostatic pressure of 30 cm H2O was used for at least 1 hour. Tensile bond strength of the different dentin bonding agents and composite or compomer materials (A: Syntac/Tetric, B: Prime & Bond NT/Spectrum TPH, C: Solobond Plus/Arabesk, D: Compoglass SCA/Compoglass, E: Dyract PSA/Dyract) was evaluated using an Zwick Universal testing machine 10 minutes after light-curing. RESULTS: Pairwise comparison showed a significant increase of bond strengths in all human plasma perfused subgroups (P< 0.05; Wilcoxon). The influence of the different dentin adhesives was significant (P< 0.001; ANOVA). The significantly highest values were observed for the composite groups Syntac/Tetric and Solobond Plus/Arabesk (P< 0.05; closed test procedure). The compomer Group D (Compoglass SCA/Compoglass) showed significantly decreased values compared to all other groups (P< 0.05; closed test procedure). Within the limitations of an in vitro study, it can be concluded that the use of human plasma might result in higher tensile bond strength compared to saline.

The effect of different desensitizing agents on initial demineralization of human root dentin.

OBJECTIVES: The aim of this study was to determine the caries-protective effect of 3 different desensitizing agents (Seal & Protect 2.0, D/Sense 2, and Gluma Desensitizer) on root dentin in vitro. METHOD AND MATERIALS: The root surfaces of 60 freshly extracted, caries-free human molars were used. After removing the cementum, the teeth were coated with an acid-resistant nail varnish, exposing 2 rectangular windows of 2 X 3 mm each on the root surface. One window served as an untreated control, and the other window was treated with 1 of the desensitizing agents. The specimens were randomly distributed among the following experimental groups: group A, D/Sense 2; group B, Seal & Protect 2.0; and group C, Gluma Desensitizer. Subsequently, all specimens were demineralized for 14 days with acidified gel (HEC, pH 4.8, 37 degrees C). Two dentinal slabs were cut from each window. The slabs were ground to a thickness of 80 microm and immersed in water. The demineralization depth was determined using a polarized light microscope. RESULTS: The nontreated control specimens showed lesions with a mean depth of 84.9 microm (+/- 6.0). In the specimens treated with the desensitizing agents, lesion depth was generally significantly reduced. Statistical analysis revealed significantly lower values for the specimens in group B in comparison with the others. CONCLUSION: Within the limitations of an in vitro investigation, it can be concluded that the demineralization of the root surface can be hampered by applying the desensitizing agents tested.

The influence of dentin adhesives on the demineralization of irradiated and non-irradiated human root dentin.

This study determined the caries-protective effects of two different dentin bonding systems (Syntac, Scotchbond) on sound and irradiated root surfaces in vitro. The root surfaces of 30 freshly extracted caries-free human molars were used. The teeth were bisected in the mesio-distal direction and all lingual halves of the teeth were irradiated. The irradiation dose of 60 Gy was fractionally applied over six weeks (2 Gy/day, 5d/wk). All halves were then coated with acid-resistant nail varnish, exposing two rectangular windows 6 mm2 each on the dentinal root surface. One window served as an untreated control, while the other was treated with one of the above mentioned dentin adhesive systems. The specimens were randomly distributed among the four experimental groups as follow: Group A: Syntac, non-irradiated; Group AR: Syntac, irradiated; Group B: Scotchbond, non-irradiated; Group BR: Scotchbond, irradiated. Subsequently, all specimens were demineralized for 14 days with acidified gel (HEC, pH 4.8, 37 degrees C). From each window, two dentinal slabs were cut. The slabs were ground to a thickness of 80 microm and submerged in water. The depth of the lesions was determined using a polarized light microscope. The non-irradiated control specimens showed lesions with an average depth of 63 microm (+/-10,2 microm). In the case of the irradiated control specimen, the lesion depth was not significantly different. In all experimental groups, the lesion depth was significantly reduced compared to the control groups. Statistical analysis revealed no significant differences between the irradiated and non-irradiated specimens. It can be concluded that demineralization of the root surface can be hampered by application of the dentin adhesive systems tested. In this study, no differences between irradiated and sound root surfaces could be detected.

Incisal tooth wear and self-reported TMD pain in children and adolescents.

PURPOSE: Incisal tooth wear may be a sign of long-term bruxing behavior. Bruxism is purported to be a risk factor for temporomandibular disorders (TMD). The aim of this population-based cross-sectional study was to determine if anterior tooth wear is associated with the self-report of TMD pain in children and adolescents. MATERIALS AND METHODS: In a population sample of 1,011 children and adolescents (mean age 13.1 years, range 10 to 18 years; female 52%; response rate 85%), TMD cases were defined as subjects reporting pain in the face, jaw muscles, and temporomandibular joint during the last month according to RDC/TMD. All other subjects were considered controls. Incisal tooth wear was assessed in the clinical examination using a 0 to 2 scale (no wear, enamel wear, dentin wear) for every anterior permanent tooth. The mean wear score for the individuals was categorized into 0, 0.01 to 0.20, 0.21 to 0.40, and 0.41+. A multiple logistic regression analysis, controlling for the effects of age and gender, analyzed the association between the categorized summary wear score and TMD. Specifically, the hypothesis of a trend between higher tooth wear scores and higher risk of TMD was tested. RESULTS: An odds ratio of 1.1 indicated, after adjusting for gender and age, no statistically significantly higher risk of TMD pain with higher tooth wear scores. CONCLUSION: Incisal tooth wear was not associated with self-reported TMD pain in 10- to 18-year-old subjects.