Relationship between dental crowding,skeletal base lengths,and dentofacial measurements

ObjectivesThe objectives of this study were to study the correlation between dental crowding, skeletal base lengths, and dentofacial measurements.Materials and methodsPretreatment dental casts and lateral cephalograms of randomly selected 45 Class I orthodontic cases divided into two groups according to the severity of mandibular crowding were evaluated. Group 1 comprised 15 patients with mandibular crowding less than 3 mm while group 2 comprised 30 patients with mandibular crowding of 3 mm or more. Maxillary and mandibular dental crowding and dentofacial measurements were compared between the two groups. For correlations the whole sample was combined to a single group where crowding was used as a continuous variable.ResultsThe only significant difference (p = 0.000) between the two groups was in the amount of dental crowding in the lower arch. Direct moderate correlation (r = 0.45; p = 0.002) between maxillary crowding and mandibular crowding, direct high correlation (r = 0.68; p = 0.000) between maxillary base length (Co-A) and mandibular base length (Co-Gn) and also direct high correlation (r = 0.74; p = 0.000) between maxillary base position (SNA angle) and mandibular base position (SNB angle) were detected. Correlation between maxillary incisor position and facial vertical dimension measured by the MP to SN angle showed inverse moderate correlation. Correlation between mandibular incisor position and the anteroposterior jaw relationship measured by the ANB angle showed direct moderate correlation.ConclusionsResults showed the presence of correlation between the skeletal dimensions and the absence of correlation between dental crowding and the same measurements. Results suggest that dental crowding is independent of the skeletal measurements.     

Metabolic control and periodontal treatment decreases elevated oxidative stress in the early phases of type 1 diabetes onset

ObjectiveRecently, increasing concern has been focused on the contribution of oxidative stress in the pathology of periodontal disease and diabetes mellitus. Firstly, the present study aimed to analyze gingival crevicular fluid (GCF), salivary, and serum oxidative status in children with type 1 diabetes mellitus (T1DM) at diagnosis and systemically healthy children with and without gingivitis. Additionally, the diabetic patients were reevaluated after diabetes and periodontal treatment.DesignThe study groups were composed of 32 T1DM patients at diagnosis, and age- and gender-matched thirty-six systemically healthy children with (G) and without (H) gingivitis. The diabetic patients who took insulin therapy (1.5 units/kg/day totally) and periodontal treatment (oral hygiene education with professional scaling) were reevaluated after 3 months. The levels of total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) were recorded.ResultsGCF, salivary, and serum OSI were elevated in group T1DM compared to the other groups at baseline (p < 0.05), and decreased in group T1DM at reevaluation compared to baseline (p < 0.05). GCF OSI was positively correlated with periodontal clinical parameters (p < 0.05). Glycated hemoglobin was positively correlated with GCF TOS (r = 0.302, p = 0.007), GCF OSI (r = 0.346, p = 0.002), salivary TOS (r = 0.326, p = 0.046), and serum TOS (r = 0.239, p = 0.044).ConclusionThe instability in the oxidative status that accompanies diabetes may be considered a significant pathogenic factor of diabetes-related periodontal inflammation.     

Study of the participation of MMP-7, EMMPRIN and cyclophilin A in the pathogenesis of periodontal disease

Background and objectivePeriodontal disease is an infectious disease resulting from the immunoinflammatory response of the host to microorganisms present in the dental biofilm which causes tissue destruction. The objective of this study was to evaluate the immunohistochemical expression of matrix metalloproteinase 7 (MMP-7), extracellular matrix metalloproteinase inducer (EMMPRIN) and cyclophilin A (CypA) in periodontal disease.DesignGingival tissue samples were divided as follows: clinically healthy gingiva (n = 32), biofilm-induced gingivitis (n = 28), and chronic periodontitis (n = 30). Histological sections of 3 μm were submitted to immunoperoxidase method and undergone quantitative analysis. The results were analyzed statistically by the Mann-Whitney and Spearman correlation tests, with the level of significance set at 0.05 (α = 0.05).ResultsImmunopositivity for MMP-7, EMMPRIN and CypA differed significantly between the three groups, with higher percentages of staining in chronic periodontitis specimens, followed by chronic gingivitis and healthy gingiva specimens (p < 0.05). Immunoexpression of CypA and MMP-7 was higher in the intense inflammatory infiltrate observed mainly in cases of periodontitis (p < 0.05). CypA expression was positively correlated with MMP-7 (r = 0.831; p < 0.001) and EMMPRIN (r = 0.289; p = 0.006). In addition, there was a significant positive correlation between probing depth and expression of MMP-7 (r = 0.726; p < 0.001), EMMPRIN (r = 0.345; p = 0.001), and CypA (r = 0.803; p < 0.001).ConclusionThese results suggest that MMP-7, EMMPRIN and CypA are associated with the pathogenesis and progression of periodontal disease.     

Frequency of periodontal pathogens in equivalent peri-implant and periodontal clinical statuses

ObjectivesThis study tested the hypotheses that there is: (1) higher bacterial frequency in peri-implantitis/periodontitis, followed by mucositis/gingivitis and peri-implant/periodontal health; (2) similar bacterial frequency between comparable peri-implant and periodontal clinical statuses.Design of studyThe presence of Porphyromonas gingivalis, Tannerella forsythia, Campylobacter rectus, Prevotella intermedia, Treponema denticola and Aggregatibacter actinomycetemcomitans was evaluated in peri-implant (n = 53) and periodontal (n = 53) health; mucositis (n = 50), gingivitis (n = 50), peri-implantitis (n = 50) and periodontitis (n = 50).ResultsThe pattern of peri-implant bacterial frequency was not as expected (peri-implantitis > mucositis > health). Except for P. intermedia (p > 0.05), bacterial frequency was higher in peri-implantitis than health (p < 0.05). The frequency of P.gingivalis and red complex species were higher in peri-implantitis than mucositis (p < 0.05). In periodontal samples, T. forsythia and T. denticola showed the expected pattern of frequency (periodontitis > gingivitis > health). The frequencies of C. rectus and T. forsythia were higher in healthy teeth/gingivitis than healthy implants/mucositis, respectively (p < 0.05). The frequency of P. gingivalis and A. actinomycetemcomitans were similar between periodontitis and peri-implantitis (p > 0.05) while all other species occurrences were higher in periodontitis than peri-implantitis (p < 0.05).ConclusionsBacterial frequency increased from peri-implant/periodontal health to peri-implantitis/periodontitis but not from mucositis/gingivitis to peri-implantitis/periodontitis. There was a trend towards higher bacterial frequency in teeth than implants.     

Diagnostic guide enabling distinction between taphonomic stains and enamel hypomineralisation in an archaeological context

ObjectiveMolar Incisor Hypomineralisation (MIH) is a structural anomaly that affects the quality of tooth enamel and has important consequences for oral health. The developmentally hypomineralised enamel has normal thickness and can range in colour from white to yellow or brown with or without surface breakdown. The possibility of finding MIH in ‘ancient populations' could downplay several current aetiological hypotheses (e.g., dioxin derivatives, bisphenols, antibiotics) without excluding the possible multifactorial aspect of the anomaly. In an archaeological context, chemical elements contained in the burial ground can stain teeth yellow or brown and therefore might create a taphonomic bias. The purpose of the present study is to test a proposed diagnostic guide enabling determination of the pathological or taphonomic cause of enamel discolouration and defects that resemble MIH present on ‘ancient teeth'.DesignTwo sample groups including MIH discoloration (n = 12 teeth) from living patients, taphonomic discoloration (n = 9 teeth) and unknown discoloration (n = 2 teeth) from medieval specimens were tested. Three non-destructive methods—Raman spectroscopy, X-ray micro-computed tomography and X-ray fluorescence were utilised.ResultsHypomineralised enamel has decreased mineral density (p < 0.0001) and increased phosphate/β-carbonate ratio (p < 0.01) compared to normal enamel whereas relative concentrations of manganese, copper, iron and lead are similar. In taphonomic discoloration, relative concentrations of these elements are significantly different (p < 0.05) to normal enamel whereas mineral density and Raman spectra profile are comparable.ConclusionsEnamel hypomineralisation can be distinguished from taphonomic staining in archaeological teeth.     

Effect of water-bath post-polymerization on the mechanical properties,degree of conversion,and leaching of residual compounds of hard chairside reline resins

ObjectivesThis study evaluated the effect of water-bath post-polymerization at 55 °C for 10 min (WB) on the content and leaching of residual compounds, degree of conversion, flexural strength, and hardness of hard chairside reline resins (Kooliner: K, New Truliner: N, Ufi Gel hard: U, and Tokuso Rebase Fast: T).MethodsLeaching experiments were made by storing specimens (n = 48) in artificial saliva at 37 ± 1 °C and analyzing residual monomers and plasticizer by HPLC. Analysis of residual monomer and plasticizer content (n = 48) was also made by HPLC. Degree of conversion (n = 40) was analyzed by using FT-Raman spectroscopy. A 3-point loading test was used to evaluate the flexural strength of the specimens (n = 80). One fragment of each flexural test specimen was then submitted to Vickers microhardness test.ResultsWB produced a significant decrease (p < 0.050) in the amount of residual compounds eluted from the materials within the first hour of immersion. With the exception of material U, WB decreased the duration of release of the residual compounds evaluated. All materials evaluated exhibited significantly (p < 0.050) lower values of residual monomer and plasticizer (material N) after WB compared with the control groups. WB increased the degree of conversion of K and T resins and the hardness of N, K, and T resins (p < 0.050). Only material K showed an increase in flexural strength after WB (p < 0.050).SignificanceImmersion of relined dentures in water at 55 °C for 10 min can be used to reduce the amounts and duration of release of residual compounds and improve mechanical properties of some of the materials evaluated.     

Probiotic intervention influences the salivary levels of Matrix Metalloproteinase (MMP)-9 and Tissue Inhibitor of metalloproteinases (TIMP)-1 in healthy adults

ObjectiveTo study the effect of orally administered Bifidobacterium animalis subsp. lactis BB-12 and Lactobacillus rhamnosus GG on the salivary levels of Matrix Metalloproteinases (MMP)-8, MMP-9 and of Tissue Inhibitor of Metalloproteinases (TIMP)-1 in healthy adults. Furthermore, the correlations between MMP-8, MMP-9 and TIMP-1 and plaque and gingival indices, salivary mutans streptococci and lactobacilli counts, and stimulated saliva secretion rate were analysed.DesignThe salivary samples originated from a randomized controlled trial where healthy student volunteers consumed probiotic or placebo lozenges twice a day for four weeks. The saliva samples were collected and clinical parameters measured at the baseline and at the end of the original study. For this study, the salivary levels of MMP-8, MMP-9 and TIMP-1 were analysed with immunofluorometric assay (IFMA) and enzyme-linked immunosorbent assay (ELISA).ResultsIn the probiotic group (n = 29), salivary MMP-9 levels increased (p < 0.01) and TIMP-1 levels decreased (p < 0.01) significantly during the intervention. Furthermore, MMP-9/TIMP-1 ratio differed significantly from the baseline level (p < 0.01). These changes were not observed in the control group (n = 31). In the whole data, salivary MMP-9 and gingival index correlated (r = 0.260, p < 0.05 at baseline and r = 0.354, p < 0.01 at the end of the study). Intergroup differences or correlations with other clinical parameters were not found. Probiotic consumption did not affect the saliva flow rate.ConclusionsIncreased MMP-9 and decreased TIMP-1 levels in saliva may indicate that probiotics have immunomodulatory effects in the oral cavity. Furthermore, increased salivary MMP-9 levels may be an indication of the defensive potential of matrix metalloproteinases.     

Effects of dexamethasone and nimesulide on bisphosphonate-related osteonecrosis of the jaw: An experimental study

ObjectiveTo evaluate the effects of dexamethasone (DEX) and nimesulide (NIM) on Bisphosphonate-related Osteonecrosis of the Jaw (BRONJ) in rats.DesignBRONJ was induced by zoledronic acid (ZA) infusion (0.2 mg/kg) in Wistar rats (n = 8), followed by extraction of the left lower first molar (BRONJ groups). Control groups (n = 40) received saline (IV). For eight weeks, DEX (0.04, 0.4, 4 mg/kg) or saline (SAL) were administered by gavage 24 h before each infusion of ZA or saline (IV), or NIM (10.3 mg/kg) was administered 24 h and 12 h before each infusion of ZA or saline (IV). The haematological analyses were conducted weekly. After euthanasia (day 70), the jaws were submitted to radiographic and microscopic analysis. Kidney, liver, spleen and stomach were analysed histopathologically.ResultsThe BRONJ groups showed a higher radiolucent area compared with the control groups (p < 0.05). Histomorphometric analysis revealed healing and new bone formation in the control groups, while the BRONJ groups exhibited devitalized bone with bacterial colonies and inflammatory infiltrate. The BRONJ-DEX 0.4 and 4 mg/kg groups had a greater number of bacterial colonies (p < 0.05) and an increased polymorphonuclear cell count compared to the saline-BRONJ group, while the BRONJ-NIM group had a lower polymorphonuclear count (p < 0.05). The BRONJ groups had leucocytosis, which was reduced by DEX administration. Treatments with DEX with or without ZA caused white pulp atrophy.ConclusionThus, DEX or NIM therapy was not effective in preventing radiographic and histopathologic events associated with BRONJ. Treatment with DEX attenuated leucocytosis post-infusion with ZA.     

Effect of fluoride toothpaste with nano-sized trimetaphosphate on enamel demineralization: An in vitro study

ObjectiveThis study evaluated the effect of toothpastes containing 1100 ppm F associated or not with micrometric or nano-sized sodium trimetaphosphate (TMP) on enamel demineralization in vitro, using a pH cycling model.DesignBovine enamel blocks (4 mm × 4 mm, n = 96) were randomly allocated into eight groups (n = 12), according to the test toothpastes: Placebo (without fluoride or TMP); 1100 ppm F (1100F); 1100F plus micrometric TMP at concentrations of 1%, 3% or 6%; and 1100F plus nanosized TMP at 1%, 3% or 6%. Blocks were treated 2×/day with slurries of toothpastes and submitted to a pH cycling regimen for five days. Next, final surface hardness (SHf), integrated hardness loss (IHL), differential profile of integrated hardness loss (ΔIHL) and enamel fluoride (F) concentrations were determined. Data were analyzed by ANOVA and Student-Newman-Keuls’ test (p < 0.05).ResultsThe use of 1100F/3%TMPnano led to SHf 30% higher (p < 0.001) and IHL ∼ 80% lower (p < 0.001) when compared to 1100F. This toothpaste also resulted in ∼64% reduction of mineral loss (ΔIHL) when compared to 1100F. Moreover, the addition of nano-sized TMP promoted increases in enamel F uptake of 90%, 160% and 100%, respectively for the concentrations of 1%, 3% and 6%, when compared to 1100F (p < 0.001).ConclusionThe addition of nano-sized TMP at 3% to a conventional toothpaste significantly decreased enamel demineralization when compared to its counterparts without TMP or supplemented with micrometric TMP.     

Association of the XPD and XRCC3 gene polymorphisms with oral squamous cell carcinoma in a Northeastern Brazilian population: A pilot study

Objectiveto evaluate the association between XPD and XRCC3 polymorphisms and oral squamous cell carcinoma (OSCC).Designthe sample consisted of 54 cases of OSCC and 40 cases of inflammatory fibrous hyperplasia (IFH). Genotypes were determined by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.ResultsXPD-Lys/Gln was more common in IFH (n = 28; 70%) than in OSCC (n = 24; 44.4%) (OR: 0.3; p < 0.05). XPD-Gln was more frequent in high-grade lesions (0.48) than in low-grade lesions (0.21) (OR: 3.4; p < 0.05). The Gln/Gln genotype was associated with III and IV clinical stages (OR: 0.07; p < 0.05). XRCC3-Met was more frequent in OSCC (0.49) than in IFH (0.35) (OR: 2.6; p < 0.05). The Met/Met genotype was associated with the presence of metastases (OR: 8.1; p < 0.05) and with III and IV clinical stages (OR: 0.07; p < 0.05).Conclusionsin this sample, the frequency of XPD-Gln in IFH suggests that this variant may protect against OSCC. The presence of the XRCC3-Met allele seems to contribute to the development of OSCC, metastases and more advanced stages in these lesions.     

Effect of cleaning protocol on silica deposition and silica-mediated bonding to Y-TZP

ObjectivesTo evaluate the effect of cleaning methods on the deposition of silica on yttria-stabilized zirconium dioxide (Y-TZP) surface and on the silane-silica mediated bond strength between Y-TZP and resin cement.MethodsY-TZP slabs were air-abraded with 30 μm silica-coated alumina particles and distributed in three groups: no cleaning, cleaning with a stream of oil-free air/water spray for 5 s and cleaning with an ultrasonic bath in water for 10 min. The distribution of Si on the Y-TZP surfaces was recorded using energy dispersive spectroscopy (EDS). After the treatment was applied, Y-TZP slabs (n = 20) received a primer application and resin cement cylinders were built on the surface. After storage (24 h) in water storage or 3 months plus thermocycling; n = 10), microshear bond strength test (μSBS) was performed. X- ray Photoelectron Spectroscopy (XPS) characterized the chemical bonds between the silica layer and the silane-containing primer. Data were analyzed using ANOVA and Tukey test, as well as Weibull analysis (α = 0.05).ResultsCleaning method had a significant effect on the amount of Si deposited on zirconia surface (p < 0.001) and, consequently, on bond strength (p < 0.001). Storage/aging also had a significant effect on bond strength (p < 0.001). Low values of Weibull moduli for bond strength were observed for all groups after aging. XPS showed silane-silica chemical interaction for all groups.SignificanceThe silica deposited by tribochemical coating to Y-TZP was removed by the cleaning methods evaluated, compromising bond strength. Stability of the bonding is also a concern when no cleaning method is applied.     

Effects of extreme cooling methods on mechanical properties and shear bond strength of bilayered porcelain/3Y-TZP specimens

ObjectivesThis study investigated the effect of extreme cooling methods on the flexural strength, reliability and shear bond strength of veneer porcelain for zirconia.MethodsVita VM9 porcelain was sintered on zirconia bar specimens and cooled by one of the following methods: inside a switched-off furnace (slow), at room temperature (normal) or immediately by compressed air (fast). Three-point flexural strength tests (FS) were performed on specimens with porcelain under tension (PT, n = 30) and zirconia under tension (ZT, n = 30). Shear bond strength tests (SBS, n = 15) were performed on cylindrical blocks of porcelain, which were applied on zirconia plates. Data were submitted to one-way ANOVA and Tukey's post hoc tests (p < 0.05). Weibull analysis was performed on the PT and ZT configurations.ResultsOne-way ANOVA for the PT configuration was significant, and Tukey's test revealed that fast cooling leads to significantly higher values (p < 0.01) than the other cooling methods. One-way ANOVA for the ZT configuration was not significant (p = 0.06). Weibull analysis showed that normal cooling had slightly higher reliability for both the PT and ZT configurations. Statistical tests showed that slow cooling decreased the SBS value (p < 0.01) and showed less adhesive fracture modes than the other cooling methods.Clinical SignificanceSlow cooling seems to affect the veneer resistance and adhesion to the zirconia core; however, the reliability of fast cooling was slightly lower than that of the other methods.     

The effect of magnesium hydroxide-containing dentifrice using an extrinsic and intrinsic erosion cycling model

ObjectiveTo evaluate, in vitro, the effect of Mg(OH)₂ dentifrice, and the influence of the number of experimental days, on the extrinsic (citric acid –CA) and intrinsic (hydrochloric acid –HCl) enamel erosion models.DesignHuman enamel slabs were selected according to surface hardness and randomly assigned to 3 groups (n = 9) as follows: non-fluoridated (negative control), NaF (1450 ppm F- positive control) and Mg(OH)₂ (2%) dentifrices. The slabs were daily submitted to a 2-h period of pellicle formation and, over a period of 5 days, submitted to cycles (3×/day) of erosive challenge (CA 0.05 M, pH = 3.75 or HCl 0.01 M, pH = 2 for 30 s), treatment (1 min −1:3 w/w of dentifrice/distilled water) and remineralization (artificial saliva/120 min). Enamel changes were determined by surface hardness loss (SHL) for each day and mechanical profilometry analysis. Data were analyzed by two-way ANOVA followed by Tukey’s test to % SHL and one-way ANOVA to profilometry (p < 0.05).ResultsThe number of experimental days influenced the erosion process for the two types of erosion models (p < 0.001). Mg(OH)₂-containing dentifrices were effective in reducing enamel extrinsic acid erosion as determined by % SHL (p < 0.001) when compared to the control group, being better than positive control (p < 0.001); however, the dentifrices were not effective for the intrinsic model (p = 0.295). With regards to surface wear, no statistically significant differences were found among the groups for CA (p = 0.225) and HCl (p = 0.526).ConclusionThe findings suggest that Mg(OH)₂ dentifrices might protect enamel against slight erosion, but protection was not effective for stronger acid erosion.     

Operator vs. material influence on clinical outcome of bonded ceramic inlays

ObjectiveThe aim of the present study was to clinically evaluate the suitability of Definite Multibond and Definite ormocer resin composite for luting of Cergogold glass ceramic inlays in a two-center trial involving two dentists.MethodsThirty-nine patients received 98 Cergogold inlays with at least one inlay luted with Definite Multibond/Definite (n = 45) and at least one inlay luted with Syntac/Variolink Ultra (n = 53) in a split mouth design. Treatments were carried out in two private practices by two operators (Operator A: n = 38; Operator B: n = 60). Forty-four cavities required caries profunda treatment, 23 cavities exhibited no enamel at the cervical margin. At baseline (2 months), and after 6, 14, 27, and 51 months of clinical service, the restorations were investigated according to modified USPHS criteria.ResultsThe drop-out rate was 3% after 4 years. After 48 months of clinical service, 21 restorations in 16 patients (9 luted with Definite, 12 with Variolink; 2 placed by operator A and 19 by operator B) had to be replaced due to inlay fracture (n = 11), tooth fracture (n = 4), hypersensitivities (n = 3), or marginal gap formation (n = 3). Seventy-seven inlays were in good condition (survival rate 89.9%, median survival time 4.2 years (95% confidence interval ±0.25; survival analysis by Kaplan–Meier algorithm). Survival rate after 4 years was 97.4% for operator A, and 75.4% for operator B (p = 0.002; Log Rank/Mantel-Cox) resulting in annual failure rates of 0.6% and 6.2%, respectively. The operators did not differently judge the clinical behaviour of the luting procedures (Mann–Whitney U-test, p > 0.05). Independent of the operator and the used luting system, the following criteria significantly changed over time: color match, marginal integrity, tooth integrity, inlay integrity, sensitivity, hypersensitivity, and X-ray control (p < 0.05; Friedman test). Significant differences between operators over the whole period were computed for the criteria marginal integrity, tooth integrity, and inlay integrity (p < 0.05, Mann–Whitney test). Differences between luting materials were only present during single recalls.SignificancesFor luting of ceramic inlays, only slight differences between the two luting systems were detectable. The operator influence on clinical outcome was clearly proven.     

Effects of polyphosphates and fluoride on hydroxyapatite dissolution: A pH-stat investigation

ObjectivesThis study investigated the immediate and sustained effect of sodium trimetaphosphate (TMP) and sodium hexametaphosphate (HMP) associated or not with fluoride (F) on hydroxyapatite (HA) dissolution using an erosion-like model, considering as well as the influence of salivary coating.DesignBaseline dissolution rates were determined for HA discs using a pH-stat system. In the first set of experiments, HA discs were treated with 1100 μg F/mL, 1% or 8% of HMP, 1% or 8% of TMP and 1100 μg F/mL associated with 1% or 8% of HMP or TMP, totaling 9 groups (n = 8). In a second phase, HA discs were kept in pooled human saliva at 37 °C for 2 h before treatment with deionised water and 1100 μg F/mL associated with 1% or 8% of HMP or TMP, totaling 5 groups (n = 8). The post-treatment dissolution rate was determined from three consecutive 30-min assays. Data were analysed using 2 and 3-way ANOVA followed by Fisher and Holm–Sidak methods, respectively (α = 0.05).ResultsAll test solutions promoted reduction in HA dissolution rate when compared to baseline control in the first post-treatment run (p < 0.001). However, a synergistic effect was only observed between fluoride and 1% HMP. Moreover, the duration of inhibitory effect was greater when 8% HMP and 1 or 8% HMP associated with F were assessed (p < 0.001). The presence of salivary coating led to higher protection for all groups when compared to discs without coating (p < 0.001).ConclusionThe reduction of HA dissolution rate, as well as the duration of this effect were influenced by fluoride, type and concentration of phosphate salt and the presence of a salivary coating.     

Quality of canal obturation assessed by micro-computed tomography: Influence of filling technique and post placement in canals shaped with Reciproc

AimTo assess by micro-computed tomography (μCT) the quality of fillings in canals shaped with Reciproc considering the effects of filling technique and post insertion.MethodologyThe canals of 60 single-rooted teeth were instrumented with Reciproc R40 and randomly assigned to four groups (n = 15): G1, single point; G2, as G1 + DT Light Post; G3, continuous wave of condensation; G4, as G3 + DT Light Post. The filling voids were quantified by μCT. Data were statistically analysed by non-parametric test (p < 0.05).ResultsFilling greater than 96% of the entire canal volume was observed in all groups. The volume of internal voids was greater in G3 than in G4 (p < 0.005).ConclusionsOur findings support the use of simplified techniques of canal shaping, filling with matching taper points and post cementation.     

Macrophage activating factor: A potential biomarker of periodontal health status

ObjectiveIn periodontitis, activated macrophages not only initiate immune responses to periodontal-pathogen infections, but also damage the periodontal tissues by releasing a series of inflammatory cytokines. Macrophage-activating factor (MAF) and macrophage-chemotactic factor (MCF) are two important mediators involved in macrophage accumulation, activation and function. This study analyzed the levels of salivary MAF and MCF in healthy individuals and those with different periodontal diseases, and assessed the usefulness of salivary MAF and MCF as diagnostic biomarkers in periodontal tissue health status.DesignNinety-five saliva specimens were collected from healthy individuals (n = 19), and patients with gingivitis (n = 19), mild periodontitis (n = 17), moderate periodontitis (n = 20), and severe periodontitis (n = 20). Pocket probing depth (PPD) and alveolar bone loss (ABL) were recorded via periodontal probing and dental radiography, respectively. Salivary MAF and MCF concentrations were assayed using enzyme-linked immunosorbent assays.ResultsMAF level tended to increase in saliva as periodontal diseases progressed (healthy periodontium < gingivitis < mild periodontitis < moderate periodontitis < severe periodontitis). The concentration of salivary MAF in periodontitis correlated positively with ABL (r = 0.758) and PPD (r = 0.779). In contrast, salivary MCF levels increased significantly only in periodontitis.ConclusionsSalivary MAF levels correlate positively with tissue destruction in periodontal diseases. It is a potential valuable biomarker that could be used to assess periodontal health status.     

Evaluation of the gingival inflammation in pregnancy and postpartum via 25-hydroxy-vitamin D3, prostaglandin E2 and TNF-α levels in saliva

BackgroundPhysiological changes and immunological modifications occur during pregnancy. The clinical and biological features of periodontal infections are affected by pregnancy. The aim of the present study was to evaluate saliva levels of 25-hydroxy-vitamin D3 (25(OH)D3), prostaglandin E2 (PGE₂) and TNF-alpha (TNF-α) in pregnancy, postpartum and non-pregnant controls.MethodsWhole saliva samples together with full-mouth clinical periodontal recordings were obtained from 59 pregnant, 47 post partum and 70 systemically healthy non-pregnant women. Groups were also evaluated according to the periodontal health status. 25(OH)D3, PGE₂ and TNF-α levels in the saliva samples were determined by enzyme-linked immunoassays. Data were statistically tested by nonparametrical tests.ResultsSaliva TNF-α and PGE₂ levels were significantly lower and 25(OH)D3 levels were significantly higher in the pregnant group than postpartum group (p < 0.0001). Saliva TNF-α and 25(OH)D3 levels were significantly higher and PGE₂ levels were significantly lower in the control group than postpartum group (p < 0.0001). In the pregnant healthy, gingivitis and periodontitis groups saliva TNF-α levels were significantly lower than postpartum and control counterparts (p < 0.0001, p = 0.032, p = 0.003 and p = 0.013; p = 0.027; p = 0.007, respectively). In control healthy, gingivitis and periodontitis groups saliva 25(OH)D3 levels were significantly higher than the postpartum counterparts (p < 0.0001, p < 0.0001, p = 0.002, respectively). In the control healthy and gingivitis groups saliva 25(OH)D3 levels were significantly higher than pregnant healthy and gingivitis (p < 0.0001).ConclusionsIn conclusion, within the limits of the present study it seems that pregnancy have an effect on parameters in saliva in relation to the periodontal status of the women. Further studies are required for better understanding of the impact of periodontal diseases on pregnancy or otherwise.     

Thermo and mechanical cycling and veneering method do not influence Y-TZP core/veneer interface bond strength

ObjectivesThe purpose of this study was to evaluate the influence of thermal and mechanical cycling and veneering technique on the shear bond strength of Y-TZP (yttrium oxide partially stabilized tetragonal zirconia polycrystal) core–veneer interfaces.Materials and methodsCylindrical Y-TZP specimens were veneered either by layering (n = 20) or by pressing technique (n = 20). A metal ceramic group (CoCr) was used as control (n = 20). Ten specimens for each group were thermal and mechanical cycled and then all samples were subjected to shear bond strength in a universal testing machine with a 0.5 mm/min crosshead speed. Mean shear bond strength (MPa) was analysed with a 2-way analysis of variance and Tukey's test (p < 0.05). Failure mode was determined using stereomicroscopy and scanning electron microscopy (SEM).ResultsThermal and mechanical cycling had no influence on the shear bond strength for all groups. The CoCr group presented the highest bond strength value (p < 0.05) (34.72 ± 7.05 MPa). There was no significant difference between Y-TZP veneered by layering (22.46 ± 2.08 MPa) or pressing (23.58 ± 2.1 MPa) technique. Failure modes were predominantly adhesive for CoCr group, and cohesive within veneer for Y-TZP groups.ConclusionsThermal and mechanical cycling, as well as the veneering technique does not affect Y-TZP core–veneer bond strength.Clinical significanceDifferent methods of veneering Y-TZP restorations would not influence the clinical performance of the core/veneer interfaces.     

Impact of high-speed sintering,layer thickness and artificial aging on the fracture load and two-body wear of zirconia crowns

ObjectiveTo investigate the impact of high-speed sintering, layer thickness and artificial aging in a chewing simulator on the fracture load (FL) and two-body wear (2BW) of 4Y-TZP crowns.Methods4Y-TZP crowns (Ceramill Zolid HT+, Amann Girrbach AG) in three different layer thicknesses (0.5, 1.0, 1.5; N = 192, n = 64/group) were manufactured using CAD/CAM technology and sintered at 1580 °C (high-speed sintering) or 1450 °C (control group). Specimens were polished in two-steps and bonded to standardized CoCr abutments with Multilink Automix (Ivoclar Vivadent). 2BW after 6000 thermo- and 1,200,000 chewing-cycles employing enamel antagonists was determined using best fit machining. FL was tested before and after artificial aging. Univariate ANOVAs, post hoc Scheffé, unpaired t-, Kruskal–Wallis- and Mann–Whitney-U-test were computed (p < 0.05).ResultsHigh-speed sintering resulted in less 2BW of the zirconia than the control group (p = 0.013). High-speed sintering (p = 0.001–0.006) and an increase in layer thickness (p < 0.001–0.012) resulted in higher FL values, while artificial aging led to a reduction of FL (p < 0.001).SignificanceAs high-speed sintering resulted in less two-body wear of the zirconia and comparable or even higher fracture load results than the control group, this cost- and time efficient alternative presents promising mechanical results.