Changes in the lip closing force of patients with class III malocclusion before and after orthognathic surgery

The purpose of this study was to examine the changes in lip pressure before and after orthognathic surgery for skeletal Class III patients. The subject groups were 32 female and 31 male patients diagnosed with mandibular prognathism and/or maxillary retrognathism who underwent orthognathic surgery. Control groups consisted of 20 women and 20 men with normal occlusion without dento-alveolar deformity. Maximum and minimum lip closing force was measured with Lip De Cum^® for the control groups and subject groups preoperatively and 6 months postoperatively. The difference between the pre- and postoperative values of the groups was examined statistically. The maximum lip closing force in men was significantly larger than that in women in both the preoperative Class III group (p = 0.0330) and the control group (p = 0.0097). The preoperative Class III group was significantly smaller than the control group in maximum lip closing force in both men (p < 0.0001) and women (p < 0.0001). The postoperative maximum lip closing force was significantly larger than the preoperative value in both men (p = 0.0037) and women (p = 0.0273) in the Class III group. This study suggested that the maximum lip closing force increases after orthognathic surgery in Class III patients.     

Ethanol consumption enhances periodontal inflammatory markers in rats

ObjectiveThe aim of this study was to assess the short term effect of ethanol administration on periodontal disease in rats.DesignRats received either ethanol 2 g/kg or water by gastric gavage twice a day. On the fifth day ligatures were tied around the molars of half of the rats to induce periodontitis. After 7 days gingival tissue was removed and assayed for inflammatory markers. Finally, hemi-mandibles were extracted to evaluate bone loss by histomorphometrical techniques.ResultsThe experimental periodontitis increased significantly the mRNA expression (p < 0.001) and activity (p < 0.001) of inducible nitric oxide synthase (iNOS) in the gingival tissue, whilst short time ethanol administration increased iNOS activity (p < 0.05) and produced an additive effect on iNOS mRNA expression augmented by periodontitis (p < 0.01). The short time ethanol administration also potentiated the periodontitis stimulatory effect on the mRNA expression of interleukin (IL)-1β (p < 0.01 and p < 0.001, in semi-quantitative and real time PCR, respectively) and on the height of periodontal ligament (p < 0.05). However, the ligature-induced periodontitis, but not ethanol administration, increased the prostaglandin E₂ content (p < 0.05) and, diminished the alveolar bone volume (p < 0.05), as compared to sham rats.ConclusionThe present results suggest that ethanol consumption could represent a risk indicator for periodontal disease since augments the expression of inflammatory markers, in healthy rats, and increases them, at short term, during the illness. However, scale longitudinal investigation and more case–control studies are needed to confirm this statement.     

Matrix metalloproteinase 8 (MMP8) gene polymorphisms in chronic periodontitis

ObjectivePrevious studies have suggested that some functional polymorphisms in the matrix metalloproteinase (MMPs) genes are associated with the risk of periodontal disease. However, to date no study has investigated MMP8 gene variants in relation to chronic periodontitis (CP). The aim of this study was to analyse polymorphisms in the MMP8 gene and their associations with microbial composition and clinical manifestation of CP.DesignA total of 619 unrelated Czech subjects were included in the present study. Two polymorphisms [?799C/T (rs11225395) and +17C/G (rs2155052)] in the MMP8 gene were studied in 341 patients with CP and 278 unrelated non-periodontitis controls. Both polymorphisms were detected using the polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) methods. Subgingival bacterial colonisation (occurrence of bacteria in subgingival pockets and gingival sulci) was investigated by a commercial semiquantitative kit in selected subjects (N = 169).ResultsOur results showed no differences in the allele and genotype frequencies of the MMP8 ?799C/T and +17C/G polymorphisms between patients with CP and controls (p > 0.05). Nevertheless, the haplotype T(?799)/C(+17) was significantly more frequent in patients with CP than in controls [43.7% vs. 37.6%, p < 0.05, OR = 1.273 (95% CI: 1.013–1.601)]. Despite significant differences determined in the occurrence of periodontal bacteria between patients with CP and non-periodontitis controls (from p < 0.000001 to p < 0.05), no significant relationships between periodontal pathogens, MMP8 polymorphisms and CP were found (p > 0.05).ConclusionsAlthough none of the investigated SNPs in the MMP8 gene was individually associated with periodontitis, specific haplotype showed association with clinical manifestation of chronic periodontitis in a Czech population.     

Characterization of mouthguard materials: Thermal properties of commercialized products

ObjectivesSeveral mechanisms have been purported to describe how mouthguards protect the orofacial complex against injury. As the properties needed for these mechanisms to be effective are temperature and frequency dependent, the specific aim of this study was to provide a comprehensive thermal characterization of commercial mouthguard materials.MethodsFive commercially representative thermoplastic mouthguard materials (Essix? Resin, Erkoflex?, Proform?-regular, Proform?-laminate, and Polyshok?) were tested. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) techniques were implemented to measure thermal transitions and mechanical properties. Measurements were conducted three times per sample. One-way ANOVA and one-sample t-tests were used to test for differences between commercial products on selected mean thermal property values.ResultsThe DSC measurements indicated no differences between commercial materials for mean glass transition (p = 0.053), onset melt (p = 0.973), or peak melt (p = 0.436) temperatures. Likewise, DMA measurements revealed no differences between commercial materials for the mean glass transition (p = 0.093), storage modulus (p = 0.257), or loss modulus (p = 0.172) properties, respectively. The one-sample t-tests revealed that glass transition temperatures were different from intra-oral temperature (p < 0.005) for all materials.SignificanceCommercialized mouthguard materials are sensitive to repetitive heating and cooling cycles, prolonged thermal treatment, and have glass transitions well below their end-use intra-oral temperature. As such, these materials are functioning as elastomers and not optimal mechanical damping materials. Dental clinicians, healthcare practitioners, or end-users should be aware that these materials are at best problematic with respect to this protective mechanism.     

Association of thalassemia major and gingival inflammation: A pilot study

ObjectivesThis cross-sectional study aimed to investigate the relationship between thalassemia major (TM) and gingival inflammation through the salivary, serum, and gingival crevicular fluid (GCF) levels of matrix metalloproteinase (MMP)-8, MMP-9 and tissue inhibitor of MMP (TIMP)-1.MethodsBiofluid samples and full-mouth clinical periodontal recordings were obtained from 29 otherwise healthy patients with TM and 25 systemically healthy (SH) individuals. Biofluid samples were evaluated by immunofluorometric assay (IFMA) and enzyme-linked immunoassays (ELISAs). Data were tested statistically by Kolmogorov Simirnov, Mann–Whitney U tests, Spearman correlation analysis.ResultsAge, smoking status, bleeding on probing, plaque index were similar in the study groups, but probing depth, gender data exhibited significant differences (p = 0.037 for both). Salivary MMP-8, MMP-9, TIMP-1 concentrations were significantly higher in the TM than SH group (p = 0.014; p < 0.001; p = 0.042, respectively). Serum TIMP-1 concentrations were significantly higher; MMP-8/TIMP-1, MMP-9/TIMP-1 molar ratios were significantly lower in the TM than SH group (p < 0.001; p = 0.005; p = 0.022, respectively). Very few GCF samples revealed biochemical data above the detection limits. Numerous correlations were found between clinical periodontal parameters and biochemical data.ConclusionsIt may be suggested that TM may exacerbate the local inflammatory response as manifested in salivary MMP-8, MMP-9, TIMP-1 levels.     

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.     

Effect of acetyl resin retentive arms on the retentive force of circumferential clasps: an in vitro study

PurposeTo compare and to evaluate the stability of the retentive force of cobalt–chromium (Co–Cr) circumferential clasps (control) to those with an acetyl resin retentive arm.MethodsSixteen specimens with a couple of circumferential clasps were made using Co–Cr over a metal model providing 0.25 mm undercuts. Eight specimens were fabricated without the anterior retentive arm, which was made later using acetyl resin (Dental D). Insertion and removal simulation test was performed through 7250 cycles. The retentive force was recorded in Newtons (N) for periods corresponding to 0, 1, 2, 3, 4, and 5 years. The data were subjected to ANOVA and Tukey test to compare periods and to Student's t test to compare groups (α = 0.05).ResultsMean (SD) is presented for Co–Cr and resin groups, respectively: 8.09(3.05) and 2.79(1.57) in period 0; 10.48(4.25) and 3.32(1.92) in 1 year; 10.09(4.15) and 3.47(1.81) in 2 years; 9.87(4.30) and 3.46(1.87) in 3 years; 9.46(3.93) and 3.27(1.59) in 4 years; 9.63(3.79) and 3.41(1.59) in 5 years. There were significant differences for Co–Cr between periods of 0 and 1 (p < 0.001), 0 and 2 (p < 0.01) and 0 and 3 (p < 0.05). In the resin group, no significant differences were found between periods (p > 0.05). Comparisons between the groups showed statistical differences for all tested periods: 0 (p = 0.0012), 1 (p = 0.0013), 2 (p = 0.0019), 3 (p = 0.0031), 4 (p = 0.0027) and 5 years (p = 0.0014).ConclusionsAcetyl resin retentive arms, even if only in the anterior clasps, can significantly reduce the retentive force, but this force remained stable after 5 years of simulated use.     

Genetic association study between Interleukin 10 gene and dental implant loss

ObjectiveThree single nucleotide polymorphisms (SNPs), ?1082, ?819 and ?592, located on the promoter region of IL10 gene have been associated with high in vitro IL-10 production and autoimmune diseases. We aim to investigate whether polymorphisms in the IL10 gene would influence dental implant loss.MethodsWe evaluated a total of 277 unrelated patients, including 185 individuals presenting at least one osseointegrated implant in function for six months or more and with no implant failure, and 92 individuals presenting at least one implant loss. DNA was extracted from buccal mucosa cells and SNPs were genotyped using TaqMan^® probes-based assays.ResultsMultiple logistic regression showed association between dental implant failure with ?819(C/T) genotype (OR = 3.27; 95% CI = 1.02–10.46; p = 0.0334). However, considering the statistical significance level α = 0.004 (adjusted by Bonferroni correction of multiple comparisons), these results lost their significance. No association of dental implant loss with genotypes and alleles of the ?1082 and ?592 SNPs, as well as IL10 haplotypes in genotype/allele forms were found (p = 0.9400; p = 0.8861).ConclusionsNeither the IL10 gene polymorphisms, nor haplotypes or other covariates were associated with susceptibility to dental implant failure in the studied population.     

The expression of antioxidant enzymes in the gingivae of type 2 diabetics with chronic periodontitis

ObjectivesThere is controversial evidence regarding the levels of antioxidant molecules in type 2 diabetes periodontitis patients. Thus, the aim of the present study was to evaluate the gene expression of antioxidant enzymes in the gingival tissue of poorly and well-controlled type 2 diabetic subjects with chronic periodontitis (CP).DesignGingival biopsies were harvested from systemically and periodontally healthy subjects (n = 12), systemically healthy subjects with CP (n = 15), well-controlled (n = 8) and poorly controlled (n = 14) diabetic subjects with CP. The messenger RNA (mRNA) levels of peroxiredoxin (PRDX) 1 and 2, catalase (CAT), glutathione peroxidase (GPX1) and superoxide dismutase (SOD) 1 and 2 were measured by quantitative polymerase chain reaction (qPCR).ResultsThe results showed that PRDX1 and GPX1 were up-regulated by periodontitis (p < 0.05), independently of the glycaemic status, whilst PRDX2 and SOD2 genes were slightly influenced by periodontitis, but significantly induced when periodontitis was associated with DM, especially under a poor glycaemic control (p < 0.05). Moreover, CAT and SOD1 expressions were not significantly influenced by any of these inflammatory disorders (p > 0.05).ConclusionIn conclusion, both PRDX1 and GPX1 were overexpressed in CP whilst PRDX2 and SOD2 were up-regulated especially in the poorly controlled diabetic group with CP.     

Effects of boric acid on experimental periodontitis and alveolar bone loss in rats

ObjectiveThe goal of the present study was to evaluate the histopathologic and morphometric effects of systemic boric acid in a rat periodontitis model.DesignTwenty-four Wistar rats were divided into three groups of eight animals each: non-ligated (NL), ligature only (LO), and ligature and treated with boric acid (BA) (3 mg/kg per day for 11 days). A 4/0 silk suture was placed in a subgingival position around the mandibular first molars; after 11 days the rats were sacrificed, and changes in alveolar bone levels were measured clinically and tissues were histopathologically examined to assess the differences amongst the study groups.ResultsThe ratio of presence of inflammatory cell infiltration (ICI) and osteoclast number in the LO group was significantly higher than that of the NL and BA groups (p < 0.05). The ratio of presence of osteoblastic activity in the LO group was significantly lower than that of the NL and BA groups (p < 0.05). Alveolar bone loss was also significantly higher in the LO group compared to the BA and NL groups (p < 005).ConclusionsThis study has demonstrated that systemic administration of boric acid reduced periodontal inflammation and alveolar bone loss in periodontal disease in rats.     

Absence or weak correlation between chewing side preference and lateralities in primary, mixed and permanent dentition

ObjectivesTo determine whether chewing side preference (CSP) is correlated to lateralities (handedness, footedness, eyedness and earedness) in primary, mixed and permanent dentitions.DesignThree-hundred subjects were divided into 3 groups: Group 1 – 100 children 3–5 years old, primary dentition; Group 2 – 100 children 6–12 years old, mixed dentition; Group 3 – 100 subjects 18–47 years old, permanent dentition. CSP was determined using a method developed by Mc Donnell et al.⁹ Subjects were given a piece of gum and the position of the chewing gum was recorded 7 times as right or left. Subjects were classified as ‘observed preferred chewing side’ (OPCS) when they performed 5/7, 6/7 or 7/7 strokes on the same side. OPCS corresponded to the CSP. Laterality tests were performed for handedness, footedness, eyedness and earedness tasks. The Chi-square (χ²) and phi correlation (r) tests were used to investigate significant correlations between CSP and sidedness.ResultsThere was a significant correlation between chewing and earedness (p = 0.00), although there was weak positive correlation (r = 0.30) for primary dentition. There were significant correlations between chewing and handedness (p = 0.02; r = 0.25) and chewing and footedness (p = 0.02; r = 0.26), however, there were weak positive correlations for mixed dentition; there were significant correlations between chewing and handedness (p = 0.02; r = 0.26); chewing and footedness (p = 0.00; r = 0.33) and chewing and earedness (p = 0.01; r = 0.29); however, there were weak positive correlations for permanent dentition.ConclusionIt may be concluded that CSP can be significantly correlated with: earedness for primary dentition; handedness and footedness for mixed dentition; handedness, footedness and earedness for permanent dentition, but these are weak positive relationships. Future work on larger samples of left- and right-sided individuals is required to validate the findings.     

Interleukin-1 receptor antagonist polymorphism (rs2234663) and periodontitis susceptibility: a meta-analysis

ObjectiveThe results of recent published studies focusing on interleukin-1 receptor antagonist (IL-1RN) gene variable number of tandem repeats (VNTR) polymorphism in periodontitis susceptibility are often conflicting. We performed a meta-analysis in order to investigate the potential association of IL-1RN VNTR polymorphism with susceptibility to either chronic (CP) or aggressive (AgP) periodontitis.DesignNineteen studies involving a total of 2011 cases and 1719 controls were searched without any language restriction. Odds ratios (ORs) along with their 95% confidence intervals (CIs) were calculated to compare the distribution of alleles and genotypes between cases and controls. Both fixed and random effects models were used to pool the data.ResultsThe IL-1RN VNTR polymorphism was marginally associated with an elevated risk of CP in overall populations (22 versus LL (L means the long alleles): OR = 1.47, 95% CI 1.00–2.18, p = 0.05), and the association was consistently significant in severe CP subgroup (OR = 4.02, 95% CI 1.84–8.80, p < 0.0005). Further stratified analysis restricted to Hardy–Weinberg equilibrium studies showed evidence for an increased risk with CP in Asians (2 allele versus L allele: OR = 1.82, 95% CI 1.31–2.54, p < 0.0005), however, a decreased risk with AgP in Caucasians (L2 versus LL: OR = 0.50, 95% CI 0.32–0.78, p = 0.002).ConclusionsThis meta-analysis suggested that IL-1RN VNTR polymorphism might contribute to an increased risk on CP and a decreased risk on AgP. However, further well-designed studies with large sample size are needed to determine the robustness of these observations in different populations.     

Setting characteristics and cavity adaptation of low-shrinking resin composites

ObjectivesThe aim of this study was to evaluate the setting characteristics of low-shrinking resin composites and examine the possible interactions with curing efficiency and marginal adaptation in dentin cavities.MethodsThe materials tested were Ceram X Mono/CM, Premise/PR, Clearfil Majesty/CM, ELS/EL, and Filtek Silorane/FS. Polymerization shrinkage strain (%S), strain rate (%S_r) and time at maximum strain rate (t_max) were measured using the bonded disk method. Curing efficiency was measured on the top and bottom surfaces of composites with ATR-FTIR spectroscopy. Marginal adaptation was measured in unbonded (%VVF) and bonded (%XVF) specimens by computerized X-ray microtomography (micro-XCT). The % linear length of the interfacial gaps along the cavity margins (%LD) and the maximum gap width (WD_max) were calculated under optical microscopy on sectioned specimens. Statistical analysis was performed with one- and two-way ANOVA, Bonferroni's post hoc test and Pearson's correlation coefficient.ResultsThe %S values ranged from 1.34% (FS) to 2.29% (CX), while %S_r ranged from 0.06%s^?1 (FS) to 0.15%s^?1 (CX). %VVF values extended from 1.9% (FS) to 5.3% (CX) and for %XVF from 1.98% (FS) to 3.35% (CX). The values for %LD ranged from 36.52% (FS) to 81.28% (CX). Linear regression showed strong positive correlation for %S_r and t_max with %VVF (r² = 0.884 and r² = 0.927) and also for %S_r and t_max with %LD (r² = 0.823 and r² = 0.869).Significance%S_r and t_max are more representative than %S in determining the setting pattern of the materials and are strongly correlated to marginal adaptation. The silorane material showed better behavior than the dimethacrylate materials in setting shrinkage and marginal adaptation.     

Quantification of tryptase-TIM-3 double-positive mast cells in human chronic periodontitis

ObjectivesMast cells (MCs) are implicated in the pathogenesis of allergic reactions and inflammatory conditions through the release of inflammatory mediators. So far limited attention has been given to the role of MCs in periodontitis. T cell immunoglobulin mucin domain (TIM)-3 is an immunomodulatory molecule and influences MC function. However, whether TIM-3 is expressed on MCs in the process of human periodontal disease has not been reported. Therefore, we identified MCs by toluidine blue staining and examined the expression of TIM-3 on tryptase-positive MCs in different severities of human chronic periodontitis using double-immunofluorescence staining in this study.Material and methodsA total of 83 human periodontal specimens were involved in this study, including healthy control tissues (n = 25), chronic moderate periodontitis (n = 28), and chronic severe periodontitis (n = 30). The gingival specimens were fixed in 10% buffered formalin, stained with haematoxylin and eosin for histopathology, with toluidine blue for MCs, and with double-immunofluorescence for identification of tryptase-TIM-3 double-positive MCs in gingival tissues.ResultsCompared with healthy controls, the score of gingival tissue inflammation was significantly increased in the chronic moderate periodontitis (P = 0.013) and chronic severe periodontitis (P < 0.0001), and the densities (cells/mm²) of tryptase-TIM-3 double-positive MCs were significantly increased in both the chronic moderate (P = 0.011) and severe periodontitis groups (P < 0.0001). However, compared with the chronic moderate periodontitis group, both the score of gingival tissue inflammation (P = 0.012) and the density of tryptase-TIM-3 double-positive MCs (P = 0.011) in gingival tissue were significantly increased in the severe periodontitis groups.ConclusionSignificantly increased number of tryptase-TIM-3 double-positive MCs had the similar tendency as the severity of periodontitis inflammation in human chronic periodontitis. Our data suggest that TIM-3 may have a role on MCs in human chronic periodontitis.     

Production of endogenous hydrogen sulfide in human gingival tissue

ObjectiveEndogenous hydrogen sulfide (H₂S) has recently been shown to play an important role in inflammation, but the role of endogenous H₂S in the human gingival tissue is unknown. The aim of this study was to investigate whether gingiva had enzymes for H₂S synthesis, and whether the effect of these enzymes for H₂S production changed with periodontal inflammation.DesignGingival tissues were collected from patients undergoing periodontal operation including gingivitis, moderate chronic periodontitis, severe chronic periodontitis and normal controls. RT-PCR and western blotting were performed to measure mRNA and protein levels of cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE) for H₂S production. Immunohistochemistry was carried out to detect the location of the enzymes. H₂S levels and synthesis in gingival tissue were evaluated with modified methylene blue method.ResultsThe mRNA and protein of CBS and CSE were both expressed in human gingiva and raised significantly in moderate and severe periodontitis compared of that in healthy control. CBS, but not CSE, increased in gingivitis (p < 0.05). However, there was no significant difference of H₂S level and synthesis among these groups (p > 0.05).ConclusionsBoth CBS and CSE were expressed in human gingival tissue. The mRNA and protein levels of CBS and CSE were up-regulated in periodontitis.     

The accuracy of three-dimensional prediction planning for the surgical correction of facial deformities using Maxilim

The motivation for orthognathic surgery is to improve facial appearance and quality of life. This study aimed to validate a three-dimensional (3D) orthognathic planning programme (Maxilim) for predicting soft tissue changes following Le Fort I advancements. Cone beam computed tomography (CBCT) scans were taken before surgery (T₁) and at 6–12 months after surgery (T₂) for 13 patients. For each patient the 3D hard tissue changes between T₁ and T₂ were determined by CBCT superimposition on the cranial vault. Using Maxilim, each patient's skeletal movements were used to generate a 3D soft tissue prediction. The actual soft tissue mesh at T₂ was compared to the predicted mesh. The face was divided into areas: nose, right and left nares, right and left paranasal regions, upper and lower lip, and chin. The absolute distance between meshes for each region was calculated. A one-sample t-test showed the distances between the meshes for all of the areas were within 3 mm (P < 0.05), except for the upper lip which was greater than 3 mm (P = 0.577). Using Maxilim, 3D soft tissue predictions for Le Fort I advancements were clinically satisfactory in the regions assessed, but associated with marked errors around the region of the upper lip.     

Effect of composition, viscosity and thickness of the opaquer on the adhesion of resin composite to titanium

ObjectivesThe objectives of this study were to determine the bond strength of powder-liquid and paste opaquers with different chemical compositions and viscosity to a metal substructure when they were applied in two thicknesses and to evaluate the failure modes after the bond strength test.MethodsTitanium plates (51 mm × 25 mm × 1 mm) (n_plates = 25, N = 80, n = 10 per group) were conditioned with chairside silica coating (CoJet-Sand, 30 μm silica coated Al₂O₃) from a distance of approximately 10 mm at a pressure of 2.8 bar for 15 s/cm² and silanized. Four types of opaquers, namely one powder-liquid (Sinfony, 3 M ESPE), and three paste opaquers [(Cimara, Voco), (Monopaque, Ivoclar Vivadent), (Cavex Experimental, Cavex)] were applied either in 0.25 or 0.50 mm thicknesses using standard polyethylene molds and photo-polymerized. Resin composite (Quadrant Posterior Dense, Cavex) was applied incrementally and photo-polymerized. The specimens were thermocycled (5–55 °C, 6000 cycles) prior to shear bond strength test (1 mm/min). Failure types were analyzed using an optical microscope and scores were given according to the modified Adhesive Remnant Index (ARI) (Score 0 = no opaquer on the surface, Score 1 = <1/2 covered with opaquer, Score 2 = >1/2 covered with opaquer, Score 3 = completely covered with opaquer).ResultsWhile thickness did not significantly affect the bond strength results (p = 0.523), type of opaquers had a significant influence on the results (p < 0.01) (Univariate ANOVA, Tukey's test). Interaction terms between thickness and opaquer type were significant (p < 0.01). Debonded specimens during thermocycling were considered as 0 MPa. At both 0.25 and 0.5 mm thicknesses, powder-liquid based opaquer (Sinfony) showed significantly higher results (8.4 ± 5.6 and 8.4 ± 4.9 MPa, respectively) than those of other opaquers (1.4 ± 1 to 4.3 ± 3.8 MPa) (p < 0.05). Only when Cimara was applied in 0.25 mm (6.9 ± 4.2 MPa), there were no significant differences with Sinfony (p > 0.05). The lowest results in both thicknesses were obtained from Monopaque (4 ± 3.8 to 1.6 ± 1 MPa, respectively) and Cavex (1.4 ± 1 to 4.2 ± 2.9 MPa, respectively) paste opaquers. In all opaquers, the incidence of Score 0 (30) was more frequent followed by Score 1 (27) and Score 2 (20).SignificanceThe use of powder-liquid opaquer in order to mask the metal in repair actions provided higher bond strength than those of the paste opaquers in both thin and thick applications. In all opaquers, the incidence of adhesive failure between the opaquer and the metal was more common implying inadequate adhesion.     

Improving the standard of the standard for glass ionomers: An alternative to the compressive fracture strength test for consideration?

ObjectivesThree strength tests (compressive, three point flexure and biaxial) were performed on three glass ionomer (GI) restoratives to assess the most appropriate methodology in terms of validity and reliability. The influence of mixing induced variability on the data sets generated were eliminated by using encapsulated GIs.MethodsSpecimen groups of 40 (eight batches of n = 5) cylinders (6.0 ± 0.1 mm height, 4.0 ± 0.1 mm diameter) for compressive fracture testing, bars (25.0 ± 0.1 mm length, 2.0 ± 0.1 mm height, 2.0 ± 0.1 mm width) for three point flexure testing and discs (13.0 ± 0.1 mm diameter, 1.0 ± 0.1 mm thickness) for biaxial flexure testing were randomly prepared by an operator. The strength data sets for each GI restorative were pooled and one-way analyses of variance (ANOVAs) were conducted to compare between GI restoratives (p = 0.05). The coefficient of variation (CoV) values for each test were pooled and a one-way ANOVA was conducted to test for differences between the reliability of the three tests.ResultsFor the GI restoratives, the one-way ANOVA showed significant differences when tested in compression (p = 0.001) but not when tested in three point (p = 0.271) or biaxial (p = 0.134) flexure. The pooled CoV values showed no significant difference between the three strength tests (p = 0.632).ConclusionsThe compressive fracture strength test specified for GIs in the International Organisation for Standardisation (ISO 9917-1: 2003) should be replaced and should no longer be advocated for the predictive performance modelling of GI restoratives.     

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.     

Bond strength durability of a resin composite on a reinforced ceramic using various repair systems

ObjectivesThis study compared the durability of repair bond strength of a resin composite to a reinforced ceramic after three repair systems.MethodsAlumina-reinforced feldspathic ceramic blocks (Vitadur-α^®) (N = 30) were randomly divided into three groups according to the repair method: PR-Porcelain Repair Kit (Bisco) [etching with 9.5% hydrofluoric acid + silanization + adhesive]; CJ-CoJet Repair Kit (3M ESPE) [(chairside silica coating with 30 μm SiO₂ + silanization (ESPE^®-Sil) + adhesive (Visio?-Bond)]; CL-Clearfil Repair Kit [diamond surface roughening, etching with 40% H₃PO₄ + Clearfil Porcelain Bond Activator + Clearfil SE Bond)]. Resin composite was photo-polymerized on each conditioned ceramic block. Non-trimmed beam specimens were produced for the microtensile bond strength (μTBS) tests. In order to study the hydrolytic durability of the repair methods, the beam specimens obtained from each block were randomly assigned to two conditions. Half of the specimens were tested either immediately after beam production (Dry) or after long-term water storage (37 °C, 150 days) followed by thermocyling (12,000 cycles, 5–55 °C) in a universal testing machine (1 mm/min). Failure types were analyzed under an optical microscope and SEM.ResultsμTBS results were significantly affected by the repair method (p = 0.0001) and the aging conditions (p = 0.0001) (two-way ANOVA, Tukey's test). In dry testing conditions, PR method showed significantly higher (p < 0.001) repair bond strength (19.8 ± 3.8 MPa) than those of CJ and CL (12.4 ± 4.7 and 9.9 ± 2.9, respectively). After long-term water storage and thermocycling, CJ revealed significantly higher results (14.5 ± 3.1 MPa) than those of PR (12.1 ± 2.6 MPa) (p < 0.01) and CL (4.2 ± 2.1 MPa) (p < 0.001). In all groups when tested in dry conditions, cohesive failure in the composite accompanied with adhesive failure at the interface (mixed failures), was frequently observed (76%, 80%, 65% for PR, CJ and CL, respectively). After aging conditions, while the specimens treated with PR and CJ presented primarily mixed failure types (52% and 87%, respectively), CL group presented mainly complete adhesive failures at the interface (70%).SignificanceHydrolytic stability of the repair method based on silica coating and silanization was superior to the other repair strategies for the ceramic tested.