Stiffness effect of using polywave or monowave LED units for photo-curing different bulk fill composites.

We investigated three bulk fill composites (Mat1, Mat2, Mat3) cured by two polywave (Poly1, Poly2) and one monowave (Mono) lamps. We used infrared spectroscopy, nanoindentation and atomic force microscopy to assess degree of conversion (DC), stiffness, and roughness after polishing, respectively. Mat2 exhibited the highest DC with Poly1 and second highest with Mono, however was the less stiff. Both Mat1 and Mat3 showed highest DC with Poly2, while Poly1 scored better than Mono. Mat3 scored better than Mat1 and was the third highest when cured with Poly2. For each composite cured by different lamps the stiffness ranked same as the DC. However, roughness did not correlate with hardness. Absolute stiffness value depends on composite formulation. Polywave lamps work better than monowave but not in all cases, as Mat2 showed higher DC with Mono than with Poly2. However, all lamps guarantee a DC≥50% but Mono for Mat1.

Bacterial adhesion on direct and indirect dental restorative composite resins: An in vitro study on a natural biofilm.

STATEMENT OF PROBLEM: Both direct and indirect techniques are used for dental restorations. Which technique should be preferred or whether they are equivalent with respect to bacterial adhesion is unclear. PURPOSE: The purpose of this in vitro study was to determine the affinity of bacterial biofilm to dental restorative composite resins placed directly and indirectly. MATERIAL AND METHODS: Five direct composite resins for restorations (Venus Diamond, Adonis, Optifil, Enamel Plus HRi, Clearfil Majesty Esthetic) and 3 indirect composite resins (Gradia, Estenia, Signum) were selected. The materials were incubated in unstimulated whole saliva for 1 day. The biofilms grown were collected and their bacterial cells counted. In parallel, the composite resin surface morphology was analyzed with atomic force microscopy. Both bacterial cell count and surface topography parameters were subjected to statistical analysis (α=.05). RESULTS: Indirect composite resins showed significantly lower levels than direct composite resins for bacterial cell adhesion, (P<.001). No significant differences were observed within the direct composite resins (P>.05). However, within the indirect composite resins a significantly lower level was found for Gradia than Estenia or Signum (P<.01). A partial correlation was observed between composite resin roughness and bacterial adhesion when the second and particularly the third-order statistical moments of the composite resin height distributions were considered. CONCLUSIONS: Indirect dental restorative composite resins were found to be less prone to biofilm adhesion than direct composite resins. A correlation of bacterial adhesion to surface morphology exists that is described by kurtosis; thus, advanced data analysis is required to discover possible insights into the biologic effects of morphology.

Minimally invasive prosthetic procedures in the rehabilitation of a bulimic patient affected by dental erosion.

The population affected by dental erosion due to bulimia is generally very young. This population group has a high aesthetic requirement; the dentition in these patients is severely damaged, especially in the anterior maxillary quadrant. In terms of treatment, it is still controversial whether an adhesive rehabilitation is preferable to a longer-lasting but more aggressive conventional treatment, such as full-crown coverage of the majority of teeth. This case report describes the prosthetic rehabilitation of a young female patient previously affected by bulimia nervosa and presenting erosion of the maxillary teeth. The prosthetic rehabilitation was performed through indirect adhesive restorations of the anterior teeth and direct restorations of the posterior teeth. A clinical follow-up after 4 years showed that the occlusion remained satisfactorily restored. Posterior direct composite resin restorations and anterior indirect adhesive composite restorations proved to be an effective time and money-saving procedure to rehabilitate patients affected by dental erosion. Adhesive rehabilitation provides a functional and good aesthetic result while preserving tooth structure. Key words:Bulimia, dental erosion, composite resin, veneers.

Indirect composite restorations luted with two different procedures: A ten years follow up clinical trial.

OBJECTIVES: The aim of this clinical trial was to evaluate posterior indirect composite resin restoration ten years after placement luted with two different procedures. STUDY DESIGN: In 23 patients 22 inlays/onlays (Group A) were luted using a dual-cured resin composite cement and 26 inlays/onlays (Group B) were luted using a light cured resin composite for a total of 48 Class I and Class II indirect composite resin inlays and onlays. The restorations were evaluated at 2 time points: 1) one week after placement (baseline evaluation) and 2) ten years after placement using the modified USPHS criteria. The Mann-Whitney and the Wilcoxon tests were used to examine the difference between the results of the baseline and 10 years evaluation for each criteria. RESULTS: Numerical but not statistically significant differences were noted on any of the recorded clinical parameters (p>0.05) between the inlay/onlays of Group A and Group B. 91% and 94 % of Group A and B respectively were rated as clinically acceptable in all the evaluated criteria ten years after clinical function. CONCLUSIONS: Within the limits of the study the results showed after ten years of function a comparable clinical performance of indirect composite resin inlays/onlays placed with a light cure or dual cure luting procedures. Key words:Light curing composite, dual curing composite, indirect composite restoration, inlays/onlays, clinical trial.

Effectiveness of nano-hydroxyapatite toothpaste in reducing dentin hypersensitivity: a double-blind randomized controlled trial.

OBJECTIVE: The present double-blind randomized clinical trial aimed to compare the efficacy in reducing dentin hypersensitivity of a dentifrice formulation containing nano-hydroxyapatite with a fluoride dentifrice and a placebo. METHOD AND MATERIALS: 105 subjects were recruited to participate in the study. A computer-generated random table with blocking to one of the three study treatments was used in order to have 35 subjects per group: 1) nano-hydroxyapatite 15% toothpaste, fluoride-free; 2) fluoride toothpaste; 3) placebo. Groups 1, 2, and 3 were instructed to brush their teeth for 2 minutes twice a day with the provided toothpaste. The participant's dentin hypersensitivity was evaluated at baseline and after 2 and 4 weeks using airblast and tactile tests. In addition, a subjective evaluation using a visual analog scale (VAS) was used. RESULTS: Significantly lower values of cold air sensitivity and tactile sensitivity (P<.001) were found for the test group at 2 weeks and 4 weeks. In addition, statistically significantly (P<.001) lower values of sensitivity were reported for group 1 compared to groups 2 and 3, at 2 and 4 weeks respectively. The VAS scores were significantly lower (P<.001) in the test group at 2 and 4 weeks compared to baseline and to the control groups. CONCLUSION: The findings of the present study encourage the application of nano-hydroxyapatite in fluoride-free toothpaste as an effective desensitizing agent providing quick relief from symptoms after 2 and 4 weeks.

Jaw clenching effects in relation to two extreme occlusal features: patterns of diagnoses in a TMD patient population.

OBJECTIVE: The aim of this investigation was to compare the pattern of temporomandibular disorder (TMD) diagnoses in clenching patients with different occlusal features, the null hypothesis being that no between-group differences exist. MATERIALS AND METHODS: Two groups of subjects receiving a jaw clenching diagnosis and having large overjet or anterior open bite (Group A; N=45, 75.5% females, mean age: 38.1 +/- 15.9 years) or normal occlusion (Group B; N=69, 71% females, mean age: 34.6 +/- 13.8 years) were recruited among a TMD patient population and were given Research Diagnostic Criteria for TMD (RDC/TMD) axis I diagnoses, namely, group I muscle disorders, group II disc displacements, and group III arthralgia/osteoarthritis/osteoarthrosis. MAJOR FINDINGS: The distribution of RDC/TMD single and combined group diagnoses was significantly different between the two groups (P<0.05), with Group A subjects showing a higher prevalence of multiple diagnoses (60% versus 43.3%), as well as a higher prevalence of combined RDC/TMD axis I group II and III diagnoses (37.8% versus 20.2%). All TMD signs and symptoms were more frequent in the patients with large overjet or anterior open bite with respect to the patients with normal occlusion. CONCLUSION: In a TMD patient population, jaw clenching may have different consequences in subjects with large overjet or anterior open bite with respect to subjects featuring normal occlusion.

Effects of non-surgical periodontal therapy on the glomerular filtration rate of the kidney: an exploratory trial.

OBJECTIVE: To determine whether non-surgical periodontal treatment (PT) would exert, in subjects with generalized chronic periodontitis (GCP), some beneficial effect on renal function as indicated by surrogate measures of the glomerular filtration rate (GFR). MATERIAL AND METHODS: Twenty GCP systemically healthy subjects were treated with PT. Serum samples were collected at baseline and 1 day, 7, 30, 90 and 180 days after treatment. GFR was evaluated using cystatin C, a serum marker and modification of diet in renal disease (MDRD), an equation involving creatinine, urea and albumin. Serum markers of systemic inflammation such as C-reactive protein (CRP), D-dimer, serum amyloid A (SAA) and fibrinogen were also assessed. RESULTS: The cystatin C level decreased significantly from baseline to the end of the trial (p<0.01). Conversely, MDRD did not vary. A significant inflammatory reaction was produced by PT in the short term. Greater increases were noted for CRP and SAA within 24 h (p<0.001 versus baseline), while D-dimer (p<0.05) and fibrinogen (p<0.01) showed mild variations. The values of inflammatory markers were normalized after 30 days. CONCLUSIONS: GFR, as assessed by cystatin C levels, may be positively affected by PT. Because of the exploratory nature of this trial, further research is needed to investigate this preliminary finding.

Lack of short-term adjunctive effect of systemic neridronate in non-surgical periodontal therapy of advanced generalized chronic periodontitis: an open label-randomized clinical trial.

AIM: To determine if the adjunctive use of intra-muscular neridronate (NE) during non-surgical periodontal treatment (PT) provides, in patients with generalized chronic periodontitis (GCP), adjunctive benefits as compared with PT alone 3 months after the completion of a 3-month NE therapy. MATERIAL AND METHODS: Sixty GCP healthy patients were randomly assigned to control (CG) or test group (TG). CG patients received PT only. Thirty subjects in TG also received adjunctive NE (12.5 mg in an i.m. injection/week for 3 months). Clinical parameters were evaluated at baseline, at the end of NE treatment (3 months after PT) and 3 months after the completion of NE treatment (6 months after the beginning of PT). RESULTS: Groups were balanced at baseline and all clinical parameters showed improvement between baseline and follow-ups. At 6 months improvements from baseline at sites with deep pocket depth (>or=7 mm) were 3.2 mm [95% confidence interval (CI): 2.7-3.9] in CG and 3.0 mm (95% CI: 2.3-3.8) in TG with a non-significant difference of 0.2 mm (95% CI: -1.0-0.5; ANCOVA; p=0.549) between groups. Secondary outcomes did not show significant differences between groups. No major adverse events were reported. CONCLUSIONS: The adjunctive use of NE during PT did not result in additional short-term improvements in periodontal conditions of GCP patients when compared with PT.

The influence of storage condition and duration on the resistance to fracture of different fiber post systems.

PURPOSE: To evaluate the effects of storage condition and duration on the resistance to fracture of different fiber post systems (and to morphologically assess the post structure before and after storage. METHODS: Three types of fiber posts (DT Light Post, GC Post, FRC Postect Plus) were divided in different groups (n = 12) according to the storage condition (dry at 37 degrees C; saline water at 37 degrees C; mineral oil at 37 degrees C and storage inside the roots of extracted human teeth immersed in saline water at 37 degrees C) and duration (6, 12 months). A universal testing machine loading at a 90 degrees angle was employed for the three-point bending test. The test was carried out until fracture of the post. A 3-way ANOVA and Tukey's test (alpha = 0.05) were used to compare the effect of the experimental factors on the fracture strength. Two posts of each group were observed before and after the storage using a scanning electron microscope. RESULTS: Storage condition and post type had a significant effect on post fracture strength (P < 0.05). The interaction between these factors was significant (P < 0.05). Water storage significantly decreased the fracture strength, regardless of the post type and the storage duration. Storage inside roots, in oil, and at dry conditions did not significantly affect post fracture strength. SEM micrographs revealed voids between fibers and resin matrix for posts stored in water. Posts stored under the other conditions showed a compact matrix without porosities.

The effect of different storage conditions and duration on the fracture strength of three types of translucent fiber posts.

OBJECTIVES: (a) To evaluate the effects of storage duration, storage condition and type of fiber post on post fracture strength. (b) To morphologically evaluate the post structure before and after storage. METHODS: Three types of fiber posts were divided in different groups (n=14) according to the storage duration (1, 6, 12 months), and storage condition (dry at 37 degrees C; saline water at 37 degrees C; mineral oil at 37 degrees C and storage inside the roots of extracted human teeth immersed in saline water at 37 degrees C). Specimens were loaded in a universal testing machine with a compressive load until fracture. A 3-way ANOVA and Tukey's test (alpha=.05) were used to compare the effect of the experimental factors on the fracture strength. Two posts of each group were observed before and after the storage using a scanning electron microscope. RESULTS: Storage conditions and post type, had a significant effect on post fracture strength (p<0.05). The interaction between these factors was significant (p<0.05). Water storage significantly decreased the fracture strength, regardless of the post type and the storage duration. Storage inside roots, in oil, and at dry conditions did not significantly affect post fracture strength. SEM micrographs revealed voids between fibers and resin matrix for posts stored in water. Posts stored under the other conditions showed a compact matrix without porosities. SIGNIFICANCE: Fiber posts placed inside human root canals immersed in water are not affected by the detrimental effect of water.

Fracture resistance of fiber posts: combinations of several small posts vs. standardized single post.

PURPOSE: To determine the fracture resistance of different sizes of standardized single fiber posts and the combinations of multiple small experimental posts. METHODS: Single posts in three different sizes (1, 2 and 3; DT Light Posts, RTD; DT), as control, and seven different combinations of experimental small posts (Abrasive Technology), reproducing the sizes of several endodontic files were cemented in endodontic resin blocks. The combinations of small posts were made combining 2-4 small posts so as to reach the sizes of standardized DT posts. The posts were loaded at an angle of 45 degrees to the long axis of the block using a crosshead speed of 1 mm/minute until specimen failure. Ten posts/combinations were tested. Statistical analysis was performed using one-way ANOVA followed by Tamhane test for the post hoc comparisons (P < 0.05). RESULTS: For the single posts, fracture resistance increased when increasing the diameter of the post. The use of multiple posts resulted in fracture resistances comparable to that of the single post for two of the three diameters studied (DT1 and DT2). For the largest diameter (DT3), the use of multiple posts resulted in lower fracture resistances than did the single post.

The effect of application sustained seating pressure on adhesive luting procedure.

OBJECTIVES: To evaluate the effect of short versus long application seating pressure on the bond strength of resin blocks, luted with a dual-cured resin cement (Panavia F) to pre-coated or non pre-coated dentin with an hydrophobic light-cured adhesive (Clearfil Protect Bond). METHODS: Sixteen non-carious human third molars were randomly divided into six Groups (four teeth each). Cylindrical composite blocks were luted with Panavia F (Group Ia) and with Clearfil Protect Bond with Panavia F (Group IIa) and seating pressure was applied for 5s. In Groups Ib and IIb, the two bonding procedures were respectively repeated, but the resin cylinder was maintained under constant pressure during the entire 3min polymerization period for the resin cement. After storing in distilled water for 24h, 0.9mmx0.9mm sticks were produced from these luted specimens for microtensile bond testing and SEM examination. RESULTS: The use of Clearfil Protect Bond with Panavia F produced higher bond strengths than the use of Panavia F (p<0.05). Extending the time of pressure application up to 3min increased the bond strength (p<0.001) and improved the integrity of the interfacial quality. SIGNIFICANCE: The application of sustained seating pressure during luting procedures and the additional use of a hydrophobic light-cured adhesive both improve the final bond strength of the resin cement.

The effect of immediate versus delayed cementation on the retention of different types of fiber post in canals obturated using a eugenol sealer.

Post can be placed immediately after the completion of the endodontic procedure or at a later stage after setting of the sealer. In this in vitro study, post space preparation and post cementation were performed immediately (group 1), 24 h (group 2), and 7 days (group 3) after root filling. A control group with no root canal obturation was included (group 4). Each group was further divided into three subgroups, according to the post type and to the materials used for luting the post. A push-out test was performed to evaluate post-root canal dentin interfacial strength. Differences among experimental groups were analyzed with two-way ANOVA and the Tukey test. Significant differences (p < 0.05) in interfacial strengths were observed for the factors post cementation interval and post type. Clinicians should be careful in performing immediate cementation of fiber posts, as delayed cementation shows higher post-dentin interfacial strengths irrespective of the post type.

Unusual asymptomatic giant sialolith of the submandibular gland: a clinical report.

This report presents an unusual case of asymptomatic sialolith of the submandibular gland. A 61-year-old man was referred to our department for multiple extractions. An ortopantomographic exam revealed the existence of a large radiopacity in the right premolar mandibular region. The patient was completely asymptomatic and no episodes of pain and swelling had occurred in the previous years. Ultrasonography and clinical examination confirmed the diagnosis of sialolithiasis of the submandibular duct. The calculus was removed trans-orally in local anaesthesia. The sialolith measured 22 mm and it was mainly constituted by phosphate, calcium and smaller amounts of magnesium. The bacteriological exam revealed the presence of Streptococcus Mitis, Streptococcus Salivarius and non-pathogenic Neisserie. Postoperative course was uneventful. Even a sialolith of significant dimensions may not be symptomatic. Nevertheless, the likelihood of future complications may constitute an indication for surgical removal of abnormal asymptomatic sialoliths.

Is an oxygen inhibited layer required for bonding of resin-coated gutta-percha to a methacrylate-based root canal sealer?

Removal of the oxygen inhibition layer from the surface of resin-coated gutta-percha cones during packaging has been hypothesized for their weak adhesion to a methacrylate-based root canal sealer, resulting in their frequent delamination from the sealer after root canal obturation. This study examined the feasibility of creating oxygen inhibition layers on resin-coated gutta-percha cones via the adjunctive application of a dual-cured dentin adhesive just before bonding. Composite cylinders were bonded with EndoREZ to flat, resin-coated gutta-percha disks and similar disks that were post-treated with Prime&Bond NT Dual Cure adhesive and stressed to failure using a modified microshear testing design. Although shear strengths for both groups were relatively low, a 5-fold increase in shear strength was observed after adhesive application, with complex interfacial failures instead of complete sealer delamination from the resin-coating. In-situ dentin adhesive application appears to have merits in enhancing the coupling of resin-coated gutta-percha to methacrylate sealers.

Microvessel density and vascular endothelial growth factor (VEGF) expression in human radicular cysts.

PURPOSE: To assess vascular endothelial growth factor (VEGF) expression and microvessel density (MVD) by immunohistochemistry and to relate them to the inflammatory status in a sample of radicular cysts. METHODS: Specimens of 24 human radicular cysts were examined by immunohistochemistry using antibodies anti-VEGF and anti-CD34 and to evaluate vascular density. Integrity of the epithelium and inflammatory state of the connective tissues were evaluated and related with the immunohistochemical findings. A Spearman correlation test was utilized to compare the means of each parameter. RESULTS: VEGF immunoreactivity was detected in both epithelial and connective tissues of radicular cysts. Stromal cells showed higher levels of VEGF expression when compared to epithelial cells. MVD proved to be related to VEGF expression levels (P < or = 0.01). In addition, increased MVD was associated with high levels of inflammation (P < or = 0.01). Most of the specimens showed a massive inflammatory infiltrate in the connective tissue. The integrity of the cystic lining tend to decrease with increased inflammation.

Effect of the seating pressure on the adhesive bonding of indirect restorations.

PURPOSE: To evaluate the effect of two different techniques of seating pressure application on the adhesive-dentin bond of indirect restorations. METHODS: Eight non-carious human third molars were randomly divided in two treatment groups (four teeth each). Cylindrical composite blocks were luted with a resin cement (Panavia F). In Group 1, the seating pressure was applied for 5 seconds. In Group 2, the resin cylinder was maintained under constant pressure during the entire 3-minute polymerization period of the resin cement. After storing in distilled water for 24 hours, 0.9 x 0.9 mm sticks were produced from these luted specimens for microtensile bond testing and SEM examination. RESULTS: The Student t-test showed a significant difference (P < 0.05) in bond strength between Groups 1 and 2. SEM revealed the presence of structural defects and resin globules on the seating surface of the composites. These features were exclusively identified from Group 1 specimens and were probably caused by fluid transudation from the underlying dentin through the simplified self-etch adhesive (ED primer).

The influence of operator variability on adhesive cementation of fiber posts.

PURPOSE: The aim of this study was to evaluate the influence of the operator's experience on the outcome of fiber post cementation using an etch-and-rinse acetone-based adhesive. MATERIALS AND METHODS: Fifteen human anterior teeth were used in the study. One trained operator performed the endodontic procedures and prepared the roots for the insertion and cementation of the posts. At this point, teeth were divided into 3 groups and distributed to 3 operators to lute the posts: an expert operator (EO), a moderately experienced operator (ME), and an operator with a low level of experience (LE). Quartz fiber posts (DT Light Post #1 or #2, RTD) were used. Posts were cemented using Prime&Bond NT Dual Cure adhesive system (Dentsply Caulk) in combination with the dual-curing resin cement Calibra (Dentsply Caulk). The post retention was assessed with the "thin-slice" push-out test. One-way ANOVA was performed to examine the effect of the operator on push-out strength, followed by post-hoc multiple comparisons using Tukey's test, with the significance level set at alpha = 95%. RESULTS: The results of push-out strength testing were as follows: EO (12.44+/-3.63 MPa), ME (11.68+/-2.64 MPa), LE (11.18+/-3.12 MPa). No statistically significant differences were determined among the three groups. CONCLUSION: There was no statistically significant difference in the retention measured for fiber posts luted by operators with different levels of clinical experience. Given the parameters of this investigation, the level of operator experience in luting fiber posts does not affect post retention under laboratory conditions.