Correlation of the interleukin-29 levels in crevicular fluid and plasma with the genetic polymorphism in chronic and aggressive periodontitis patients

Objective

To assess the effect of single nucleotide polymorphism (SNP) on the Interleukin (IL-29) quantity in gingival crevicular fluid (GCF) and plasma of chronic and aggressive periodontitis patients.

Design

Patients with periodontal health (n = 30), chronic generalized periodontitis (n = 30) and generalized aggressive periodontitis (n = 30) were subjected to IL-29 quantity estimation in GCF and plasma using enzyme linked immunosorbent assay and was correlated with IL-29 SNP (rs30461) using polymerase chain reaction.

Results

IL-29 concentration in GCF and plasma was highest in aggressive periodontitis patients (114.17 ± 95.07 pg/ml and 149.69 ± 109.90 pg/ml respectively). The least concentration was found in subjects with healthy periodontium (47.50 ± 37.75 pg/ml and 54.52 ± 37.53 pg/ml) and in chronic periodontitis it was found to be 65.01 ± 41.26 pg/ml and 81.17 ± 46.23 pg/ml. The difference in the quantity of IL-29 in GCF and plasma among different groups was statistically significant (p < 0.001 and p < 0.001 respectively). rs30461 polymorphism of IL-29 analysis revealed that difference in the prevalence of A/A, A/G and G/G genotype among three groups was not statistically significant (p = 0.097).

Conclusion

Increased quantity of IL-29 in GCF and plasma of subjects with periodontitis suggests a role in pathogenesis of periodontitis and the SNP (rs30461) is not related to susceptibility to periodontitis in this population of Indian individuals.     

Mechanical properties and modeling of drug release from chlorhexidine-containing etch-and-rinse adhesives

Objectives

To evaluate the effects of chlorhexidine (CHX) addition in different concentrations into simplified etch-and-rinse adhesives on the ultimate tensile strength (UTS), water sorption (WS), solubility (SO) and the rate of CHX release over time.

Methods

We added CHX diacetate to Ambar [AM] (FGM) and XP Bond [XP] (Dentsply) in concentrations of 0, 0.01, 0.05, 0.1 and 0.2 wt%. For UTS (n = 10 for each group), adhesive specimens were constructed in an hourglass shape metallic matrix with cross-sectional area of 0.8 mm². Half of specimens were tested after 24 h and the other half after 28 days of water storage in tension of 0.5 mm/min. For WS and SO (n = 10 for each group), adhesive discs (5.8 mm × 1.0 mm) were prepared into a mold. After desiccation, we weighed and stored the cured adhesive specimens in distilled water for evaluation of the WS, SO and the cumulative release of CHX over a 28-day period. For CHX release (n = 10 for each group), spectrophotometric measurements of storage solution were performed to examine the release kinetics of CHX. We subjected data from each test to ANOVA and Tukey’ test (α = 0.05).

Results

XP Bond adhesive showed significantly more WS and SO and lower UTS than Ambar. In general, the addition of CHX did not alter WS, SO and UTS of the adhesives. XP showed a higher CHX release than AM (p < 0.05) in all concentrations and the final amount of CHX release was directly proportional to the initial CHX concentration added to the adhesives. After 28 days of water storage, approximately 20% of CHX was released from XP and 8.0–12.0% from AM.

Conclusions

Addition of CHX to commercial adhesive is a feasible method to provide a controlled release of CHX over time without jeopardizing WS, SO and UTS of the adhesives.

Significance

Manufacturers should consider adding CHX to commercial adhesives to provide a controlled release of CHX over time.     

Fit of 4-unit FDPs made of zirconia and CoCr-alloy after chairside and labside digitalization – A laboratory study

Objectives

To analyse the marginal fit of 4-unit fixed dental prostheses (FDPs) and the accuracy of three-dimensional cast-datasets using both approaches to Computer Aided Design (CAD)/Computer Aided Manufacturing (CAM): direct and indirect digitalization.

Methods

A titanium model of a 4-unit FDP was digitized by an intraoral scanning device (iTero, Align Technology, Carlstadt, US; DD, n = 12). Additionally 12 conventional impressions were taken and referring master casts were digitized by a laboratory scanner (CS2, Straumann, Basel, Switzerland; ID, n = 12). Frameworks were fabricated (CARES CADCAM GmbH, Straumann, Markkleeberg, Germany) from base metal alloy (coron, Straumann; DD-C: n = 12; ID-C: n = 12) and zirconia (zerion, Straumann; DD-Z: n = 12; ID-Z: n = 12) from the same datasets. The marginal fit of the resulting frameworks and the accuracy of the underlying datasets from DD and ID were evaluated. Data were analyzed by unpaired two sample Student's t-test with Levene-test (p < 0.05).

Results

Frameworks from group DD-C showed significantly better marginal fit than ID-C (DD-C: 56.90 ± 27.37 μm, ID-C: 90.64 ± 90.81 μm). For zirconia frameworks no differences between both digitalization methods (DD-Z: 127.23 ± 66.87 μm, ID-Z: 141.08 ± 193.17 μm) could be observed. Base metal alloy frameworks exhibited significantly better marginal fit than zirconia frameworks (DD: p < 0.001; ID: p = 0.022). Regarding the accuracy group DD showed significantly higher “trueness” than ID.

Significance

Direct and indirect digitalization lead to clinically acceptable marginal fit of 4-unit FDPs from base metal alloy and zirconia. Higher accuracy of datasets from DD leads to better marginal fit of frameworks from base metal alloy but not for ones from zirconia.     

A tentative model for d-glucose turnover in human saliva

Objective

The aim of the present study is to propose a tentative model for d-glucose turnover in human saliva. The whole saliva and the saliva from parotid and submandibular/sublingual glands were collected by use of the Salivette™.

Results

The saliva glucose concentration was measured by the hexokinase method, saliva bacteria glycolysis by use of d-[5-³H] glucose, and the saliva ATP content by the luciferase method. The concentration of glucose amounted to 43.9 ± 6.3 (n = 29), 197.5 ± 17.3 (n = 29), 104.0 ± 12.4 (n = 27) μM in whole saliva, parotid saliva and submandibular/sublingual saliva, respectively. The rate of d-glucose utilization by oral bacteria at a physiological concentration of d-glucose in saliva (50 μM) was estimated at 0.047 ± 0.003 (n = 11) nmol/min per 10⁶ bacteria. Unstimulated salivary d-glucose turnover rate, as calculated from the amount of glucose secreted in saliva which comes from parotid and submandibular and sublingual glands represented 214.6 ± 19.1%/min. In order for salivary d-glucose production to match bacterial utilization of the hexose, the total number of oral bacteria was estimated at about 2.0 × 10⁹ bacteria, in fair agreement with previously published data.

Conclusion

This study thus provides support for a tentative model for d-glucose turnover in human saliva.     

Effect of caffeine on the secretion of peroxidase in rat submandibular gland: a study of its mechanism of action

Objetive

In this work, we analysed the mechanism of action of caffeine on peroxidase secretion in the female rat submandibular gland. The signaling molecules cAMP and nitric oxide were monitored as potential mediators.

Design

The salivary gland peroxidase secretion of female albino Wistar rats was assessed by a spectroscopic method.

Results

Caffeine was found to exert an increase on peroxidase secretion in a concentration-response manner: the peroxidase secretion stimulation index (SI) (secreted peroxidase from treated/secreted peroxidase from basal) for caffeine 10 μg/ml: 2.2 ± 0.18 (P < 0.05); caffeine 100 μg/ml alone: 3 ± 0.18 (P < 0.01); +LNMMA (LN monomethyl arginine): 1 ± 0.1 (P < 0.05); caffeine 1000 μg/ml alone: 5 ± 0.35 (P < 0.01); +LNMMA: 2 ± 0.2 (P < 0.05). These results were associated with an increase in cAMP and total nitrites production. Total nitrites, SI caffeine 100 μg/ml alone: 2.8 ± 0.2 (P < 0.01); +LNMMA: 1 ± 0.08 (P < 0.05); caffeine 1000 μg/ml alone: 4.8 ± 0.3 (P < 0.01); +LNMMA: 2.3 ± 0.18 (P < 0.05).

Conclusion

It could thus be concluded that cAMP and NO are involved in the mechanism of action displayed by caffeine. This is the first report on the mechanism of action of caffeine on peroxidase secretion.     

Preventive effect of an iron varnish on bovine enamel erosion in vitro

Objective

The aim of this study was to evaluate, in vitro, the effect of an experimental varnish containing iron on the dissolution of bovine enamel by carbonated beverage.

Methods

Eighty specimens were randomly allocated to four groups (n = 20 per group), according to the following treatments: Fe varnish (FeV, 10 mmol/L Fe), F varnish (FV, 2.71% F), placebo varnish (PV) and control (not treated, NT). The varnishes were applied in a thin layer and removed after 6 h. Then, the samples were submitted to six cycles, alternating re- and demineralisation (only 1 day). Demineralisation was performed with the beverage Coca-Cola^® (10 min, 30 mL/block) and remineralisation with artificial saliva for 1 h. In order to determine the amount of enamel dissolved, the wear was analysed by profilometry. Data were analysed by ANOVA and Tukey's test (p < 0.05).

Results

The mean wear (±S.E.) was significantly lesser for the FeV (0.451 ± 0.018 μm) when compared to the other treatments. The FV caused significantly less wear (0.554 ± 0.022 μm) when compared to PV (0.991 ± 0.039 μm) and NT (1.014 ± 0.033), which did not significantly differ from each other.

Conclusions

The results suggest that the iron varnish can interfere with the dissolution of dental enamel in the presence of acidic beverages.     

mRNAs for PRPs, statherin, and histatins in von Ebner's gland tissues

A search was made for expression of genes for proline-rich proteins (PRPs) and other salivary-type proteins, including statherin and histatins, in taste-bud tissues of mice and primates because of previous genetic findings in mice (Azen et al., 1986) that Prp and taste genes for certain bitter substances are either the same or closely linked. Taste-bud tissues and other tissues were tested for specific mRNAs with labeled DNA probes by Northern blotting and in situ hybridization. It was found that PRP mRNAs were present in von Ebner's glands of mice and macaques, and that there was a much greater degree of PRP mRNA induction in mouse parotid (16-fold) than in von Ebner's gland (two-fold) after in vivo isoproterenol stimulation. This difference may be due, in part, to differences in autonomic nerve innervation. Statherin and histatin mRNAs were found in macaque taste-bud tissues containing von Ebner's gland, and statherin protein was found in human von Ebner's gland by immunohistochemistry. The finding of PRP gene expression in von Ebner's gland, whose secretions have been suggested to play a role in taste stimulation, adds further support to a possible function of PRPs in bitter tasting. The possible functions of statherin and histatins in von Ebner's gland secretions may be related to statherin's regulation of salivary calcium and histatins' antibacterial and antifungal properties.     

Oral fluid proteolytic effects on histatin 5 structure and function

Histatins are human salivary antifungal proteins that are prone to extensive enzymatic degradation upon their release into the oral cavity. Histatin proteolysis, leading to the disappearance of the intact protein can be expected to have functional consequences. Histatin 5, comprising 24 residues, is the smallest of the major salivary histatins and the most active in terms of its antifungal properties. The rate and mode of histatin 5 degradation were determined by incubating the protein in whole saliva supernatant for various time intervals. Fragmentation products were collected by reversed-phase high performance liquid chromatography (RP-HPLC), characterised structurally by matrix-assisted laser desorption/ionisation-time of flight (MALDI-TOF) mass spectrometry and functionally in a fungal growth inhibition assay. Of the 19 fragments identified, 16 were derived from single proteolytic cleavage events in histatin 5. A remarkable finding was the inter-subject consistency in the histatin 5 degradation pattern. Added histatin 5 disappeared from whole saliva supernatant at an average rate of 105 ± 22 μg/ml/h, which in part could explain the virtual absence of histatin 5 in whole saliva. Despite the rapid proteolysis of histatin 5, the early degradation mixture was as active in antifungal assays as intact histatin 5. These data demonstrate that the oral-fluid mediated proteolysis of histatin 5 represents an intrinsic biological property of whole saliva. The data also reveal that the early proteolysis phase of histatin 5 does not abolish the antifungal properties associated with this protein.     

Erosion-inhibiting potential of a stannous chloride-containing fluoride solution under acid flow conditions in vitro

Objectives

This study aimed to analyse the erosion-inhibiting potential of a single application of stannous chloride-containing fluoride solution on pellicle-covered enamel and dentine under constant acid flow conditions in vitro.

Design

Bovine enamel (n = 60) and dentine (n = 60) samples were exposed 1 h to the oral cavity of 4 healthy volunteers to allow for in situ pellicle formation. Pellicle-covered samples were randomly assigned to three groups (each n = 20 enamel and n = 20 dentine samples; 5 enamel and 5 dentine samples/volunteer) and treated once with a SnCl2/AmF/NaF (800 ppm Sn(II), 500 ppm F, pH 4.5) or a NaF solution (500 ppm F, pH 4.5) for 2 min or remained untreated (controls). Samples were eroded with hydrochloric acid (pH 2.6) in a small erosion chamber at 60 μl/min for 25 min. Calcium release into the acid was monitored in consecutive 30 s intervals for 5 min, then at 1 min intervals up to a total erosion time of 25 min using the Arsenazo III procedure. Data were statistically analysed by random-effects linear models (p < 0.05).

Results

The stannous chloride-containing fluoride solution reduced calcium loss of enamel and dentine to up to 6 min and 3.5 min, respectively. Calcium loss (% of control) amounted from 24 ± 7 (30 s) up to 93 ± 14 (6 min) in enamel and from 38 ± 13 (30 s) to 87 ± 15 (3.5 min) in dentine. The sodium fluoride solution was unable to reduce enamel and dentine erosion at any time point.

Conclusion

A single application of a stannous chloride-containing fluoride solution reduced enamel and dentine erosion up to 6 min and 3.5 min of constant acid flow, respectively.     

In vitro precision of fit of computer-aided design and computer-aided manufacturing titanium and zirconium dioxide bars

Objectives

Optical scanners combined with computer-aided design and computer-aided manufacturing (CAD/CAM) technology provide high accuracy in the fabrication of titanium (TIT) and zirconium dioxide (ZrO) bars. The aim of this study was to compare the precision of fit of CAD/CAM TIT bars produced with a photogrammetric and a laser scanner.

Methods

Twenty rigid CAD/CAM bars were fabricated on one single edentulous master cast with 6 implants in the positions of the second premolars, canines and central incisors. A photogrammetric scanner (P) provided digitized data for TIT-P (n = 5) while a laser scanner (L) was used for TIT-L (n = 5). The control groups consisted of soldered gold bars (gold, n = 5) and ZrO-P with similar bar design. Median vertical distance between implant and bar platforms from non-tightened implants (one-screw test) was calculated from mesial, buccal and distal scanning electron microscope measurements.

Results

Vertical microgaps were not significantly different between TIT-P (median 16 μm; 95% CI 10–27 μm) and TIT-L (25 μm; 13–32 μm). Gold (49 μm; 12–69 μm) had higher values than TIT-P (p = 0.001) and TIT-L (p = 0.008), while ZrO-P (35 μm; 17–55 μm) exhibited higher values than TIT-P (p = 0.023). Misfit values increased in all groups from implant position 23 (3 units) to 15 (10 units), while in gold and TIT-P values decreased from implant 11 toward the most distal implant 15.

Significance

CAD/CAM titanium bars showed high precision of fit using photogrammetric and laser scanners. In comparison, the misfit of ZrO bars (CAM/CAM, photogrammetric scanner) and soldered gold bars was statistically higher but values were clinically acceptable.     

Clinical study of tongue pain: Serum zinc,vitamin B12, folic acid,and copper concentrations,and systemic disease

The aim of this retrospective study of patients with tongue pain who showed no improvement after initial treatment and examination was to find out if their lack of response correlated with serum concentrations of zinc, vitamin B12, folic acid, and copper, and if it was associated with coexisting systemic diseases. We studied 311 patients for whom we had data about serum concentrations of these elements, and recorded whether they had any systemic diseases and were taking medicines regularly. One patient (0.3%) had a copper concentration outside the reference range; 2 patients (0.6%) had folic acid concentrations outside the reference range. The corresponding number for vitamin B12 was 5 (2%), and for zinc 30 (10%). The systemic diseases with the highest rates were: hyperlipidaemia (n = 53, 17%), gastritis or gastric ulcer (n = 51, 16%), angina pectoris (n = 39, 13%), diabetes mellitus (n = 31, 10%), thyroid disease (n = 31, 10%), mild mental disorder (n = 27, 9%), hypertension (n = 18, 6%), cerebral infarction (n = 17, 6%), leiomyoma (n = 15, 5%) and anaemia (n = 15, 5%).     

Comparison of perioperative morbidity after LeFort III and monobloc distraction osteogenesis

We have compared distraction by monobloc and LeFort III osteotomy in the treatment of midfacial retrusion. We treated 14 patients with midface distraction (Crouzon syndrome (n = 9), Apert disease (n = 3), and other (n = 2)), 7 of whom had monobloc distraction and 7 who had LeFort III osteotomy. We compared duration of operation, peroperative blood loss, and complications. The two groups were comparable with respect to diagnosis, type of distraction (internal or external device), and duration of distraction. The operating time was longer in the monobloc than in the LeFort III group, but not significantly so (p = 0.09). The weight-adjusted blood losses were significantly different (66 ml/kg and 34 ml/kg, respectively (p = 0.05). The two groups had similar numbers of complications (p = 0.3), and similar duration of hospital stay. Both techniques seem safe. The choice of operation, therefore, should be tailored to the individual patient and the monobloc procedure should be used if indicated.     

The preventive effect of grape seed extract on artificial enamel caries progression in a microbial biofilm-induced caries model

Objectives

The aim of this study was to evaluate the effect of grape seed extract (GSE) on enamel caries lesion formation in an in vitro Streptococcus mutans biofilm model.

Methods

Enamel fragments were prepared from bovine incisors and divided into six treatment groups (n = 12): inoculated Brain Heart Infusion with 1% sucrose (BHIS), 1 mg/mL GSE, 2 mg/mL GSE, 3 mg/mL GSE, 10 ppm fluoride as NaF, and uninoculated BHIS. For biofilm formation, tooth fragments were incubated anaerobically in polystyrene 6-well tissue culture plates containing BHIS, the respective agents, and S. mutans (1 × 10⁵ CFU/mL) for 24 h at 37 °C. Culture medium was replaced with fresh BHIS and respective agents daily over a 7-day period. Following caries lesion formation, lesion depth (LD) and relative optical density (ROD) were determined by polarized light microscopy (PLM) and confocal laser scanning microscopy (CLSM), respectively, to evaluate lesion progression.

Results

LDs of the 2 mg/mL GSE group (122.86 ± 13.41 μm) and the 3 mg/mL GSE group (111.92 ± 11.39 μm) were significantly smaller than those of the 1 mg/mL GSE (198.33 ± 17.70 μm) and control groups (210.86 ± 15.50 μm) (p < 0.05). Compared with the 2 mg/mL and 3 mg/mL groups, the control and 1 mg/mL GSE groups showed significantly lower ROD values when depth was less than 200 μm, indicating greater mineral loss.

Conclusions

Dose-dependent GSE inhibits in vitro enamel caries formation due to its ability to suppress growth of S. mutans and the formation of bio?lm.

Clinical signi?cance

Grape seed extract may be a novel virulence-targeted natural antimicrobial agent for caries prevention.     

The role of spacer carbon chain in acidic functional monomers on the physicochemical properties of self-etch dental adhesives

Objectives

To evaluate the effects of acidic functional monomers with different hydrophilicity and spacer carbon chain length on the degree of conversion (DC), wettability (contact angle), water sorption (WS) and ultimate tensile strength (UTS) of experimental one-step self-etch adhesives (1-SEAs).

Methods

A series of standard resin blends was prepared with each formulation containing 15 mol% of each acidic monomer. The structural variations of the acidic monomers were MEP (spacer chain with 2 carbons), MDP (10-carbons), MDDP (12-carbons), MTEP (more hydrophilic polyether spacer) and CAP-P (intermediate hydrophilicity ester spacer). Dumbbell-shaped and disc specimens were prepared and tested for UTS and WS, respectively. DC was assessed by FTIR, while the wettability of each 1-SEA was evaluated on glass slides and flat dentine surfaces. Results were analysed with one-way ANOVA and Tukey's test (p < 0.05).

Results

The outcomes showed lower UTS for CAP-P, control blend and MEP than MTEP, MDDP and MDP (p < 0.05). The degree of conversion was statistically similar for all resins (p = 0.122). On dentine, the wettability was higher (lower contact angle) with the most hydrophilic monomer MTEP. Higher WS was attained using MTEP. Different lengths of the spacer chains did not result in different wettability and WS (p > 0.05).

Conclusion

At similar molar percentage, different acidic functional monomers induced similar degree of conversion and different UTS when included in a 1-SEA. However, the inclusion of highly hydrophilic monomer may increase the wettability on dentine and the WS.     

Cuspal deflection,strain and microleakage of endodontically treated premolar teeth restored with direct resin composites

Objectives

To measure cuspal deflection and tooth strain, plus marginal leakage and gap formation caused by polymerization shrinkage during direct resin composite restoration of root-filled premolars.

Methods

Thirty-two first and second maxillary premolars were divided into four groups (n = 8). Group 1 had standardised mesio-occlusal-distal (MOD) cavities and served as the control group. Group 2 had endodontic access and root canal treatment through the occlusal floor of the MOD cavity, leaving the axial dentine intact. Group 3 had endodontic access and root canal treatment with the mesial and distal axial dentine removed. Group 4 had endodontic access and root canal treatment with axial dentine removed and a glass ionomer base (GIC). All groups were restored incrementally using a low shrink resin composite. Cuspal deflection was measured using direct current differential transformers (DCDTs), and buccal and palatal strain was measured using strain gauges. Teeth were immersed in 2% methylene blue for 24 h, sectioned and scored for leakage and gap formation under light and scanning electron microscopy.

Results

Total cuspal deflection was 4.9 ± 1.3 μm for the MOD cavity (group 1), 7.8 ± 3.3 μm for endodontic access with intact axial dentine (group 2), 12.2 ± 2.6 μm for endodontic access without axial dentine (group 3), and 11.1 ± 3.8 μm for endodontic access with a GIC base (group 4). Maximum buccal strain was 134 ± 56, 139 ± 61, 251 ± 125, and 183 ± 63 μstrain for groups 1–4 respectively, while the maximum palatal strain was 256 ± 215, 184 ± 149, 561 ± 123, 264 ± 87 μstrain respectively. All groups showed marginal leakage; however placement of GIC base significantly improved the seal (p = 0.007).

Conclusion

Cusp deflection and strain increased significantly when axial dentine was removed as part of the endodontic access. Placement of a glass ionomer base significantly reduced tooth strain and marginal leakage. Therefore, a conservative endodontic access and placement of a glass ionomer base are recommended if endodontically treated teeth undergo direct restoration with resin composite.     

The effect of preparation designs on the marginal and internal gaps in Cerec3 partial ceramic crowns

Objectives

The purpose of this study was to evaluate the marginal and internal gaps in Cerec3 partial ceramic crowns (PCCs) of three different preparation designs in vitro using microcomputed tomography (μCT).

Methods

Cerec3 PCCs of three different preparation designs (n = 20) were fabricated according to the following: Group I-conventional functional cusp capping/shoulder preparation, Group II-horizontal reduction of cusps and Group III-complete reduction of cusps/shoulder preparation. After fixation of PCCs, the μCT scanning was performed. For obtaining the average internal gap (AIG), the μCT sections were reconstructed 3-dimensionally, and then the total volume of the internal gap was divided by the contact surface area. The 2-dimensional (2D) μCT views were used to investigate the gaps at predetermined key positions in seven bucco-lingual sections and three mesio-distal cross sections. The gaps were measured using the μCT at each reference point. Statistical analysis was performed using one-way ANOVA and Tukey's test.

Results

For the 3D reconstruction technique, the AIGs were as followed: Group I 197.3 ± 48.2 μm, Group II 171.2 ± 45.1 μm, and Group III 152.7 ± 27.1 μm. For the 2D μCT views, the gaps of each group were the smallest on the margins ranging from 35.4 ± 32.2 to 128.4 ± 69.5 μm, and the largest on the horizontal or angle walls ranging from 184.5 ± 41.2 to 406.5 ± 176.1 μm. According to the results, Group I showed larger marginal and internal gaps compared with the other groups.

Conclusions

For the PCCs, the simplified designs (Groups II and III) demonstrated superior results compared to the traditional cusp capping design (Group I). The marginal gaps were smaller than the internal gaps in all groups.     

Effects of Cachaça, a typical Brazilian alcoholic beverage,on alveolar bone loss and density: A study in peripubertal rats

Objective

The aim of the present study was to assess the impact of chronic consumption of Cachaça on alveolar bone loss (BL) induced by ligature and on alveolar bone density (BD) in peripubertal rats.

Design

Male Wistar rats were assigned into one of the following groups: Control: non-ingestion of Cachaça (n = 15); Cachaça: ingestion of ascending concentrations of Cachaça during 100 days (n = 15). 70th day after the beginning of Cachaça ingestion, one first mandibular molar received a ligature while the contralateral tooth was left unligated. After 30 days, the rats were killed. BL, BD, the positive cells for tartrate-resistant acid phosphatase (TRAP), receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) were analyzed in the furcation area of the ligated and unligated mandibular molars.

Results

The Cachaça group presented greater BL (0.75 ± 0.1 mm² for Cachaça and 0.66 ± 0.1 mm² for control group, respectively) and number of RANKL and OPG+ cells and lower BD (60.3 ± 4.2% for Cachaça and 76.8 ± 3.8% for control group, respectively) and number of TRAP+ cells around ligated teeth (p < 0.05), when compared to the control group. The Cachaça group (0.42 ± 0.02 mm²) also presented a higher BL around unligated teeth when compared to control group (0.31 ± 0.05 mm²).

Conclusions

Cachaça consumption per se and in the presence of ligature negatively affects alveolar bone by increasing the alveolar BL and reducing BD.     

Effect of temperature on composite polymerization stress and degree of conversion

Objective

To test the following hypotheses: (1) degree of conversion (DC) and polymerization stress (PS) increase with composite temperature (2) reduced light-exposure applied to pre-heated composites produces similar conversion as room temperature with decreased PS.

Methods

Composite specimens (diameter: 5 mm, height: 2 mm) were tested isothermally at 22 °C (control), 40 °C, and 60 °C using light-exposures of 5 or 20 s (control). DC was accessed 5 min after light initiation by FTIR at the specimen bottom surface. Maximum and final PS were determined, also isothermally, for 5 min on a universal testing machine. Non-isothermal stress was also measured with composite maintained at 22 °C or 60 °C, and irradiated for 20 s at 30 °C. Data were analyzed using two-way ANOVA/Tukey and Student's t-test (α = 5%).

Results

Both DC and isothermal maximum stress increased with temperature (p < 0.001) and exposure duration (p < 0.001). Isothermal maximum/final stress (MPa) were 3.4 ± 2.0b/3.4 ± 2.0A (22 °C), 3.7 ± 1.5b/3.6 ± 1.4A (40 °C) and 5.1 ± 2.0a/4.0 ± 1.6A (60 °C). Conversion values (%) were 39.2 ± 7.1c (22 °C), 50.0 ± 5.4b (40 °C) and 58.5 ± 5.7a (60 °C). The reduction of light exposure duration (from 20 s to 5 s) with pre-heated composite yielded the same or significantly higher conversion (%) than control (22 °C, 20 s/control: 45.4 ± 1.8b, 40 °C, 5 s s: 45.1 ± 0.5b, 60 °C, 5 s s: 53.7 ± 2.7a, p < 0.01). Non-Isothermal conditions showed significantly higher stress for 60 °C than 22 °C (in MPa, maximum: 4.7 ± 0.5 and 3.7 ± 0.4, final: 4.6 ± 0.6 and 3.6 ± 0.4, respectively).Clinical significance: Increasing composite temperature allows for reduced exposure duration and lower polymerization stress (both maximum and final) while maintaining or increasing degree of conversion.     

Absorption and release of protein from hydroxyapatite-polylactic acid (HA-PLA) membranes

Objectives

The aim of this study was to investigate the kinetics of protein interactions with a novel hydroxyapatite-polylactide (HA-PLA) composite membrane material.

Methods

Trilayer PLA and HA-PLA composite membranes reinforced with PLA fibres were used to absorb and release protein which was measured by a BioRad assay. The proteins used were fetal calf serum and bovine serum albumin. PLA and HA-PLA composite films were manufactured to test permeability.

Results

Maximal protein absorption was seen within 5 min of treating materials; a nearly 8-fold increase in total absorption was seen with HA-containing composites compared to those without HA. These also exhibited a more gradual and sustained release of protein for periods of up to 96 h, for example at 24 h protein concentrations released were 2.20 ± 2.80 and 0.49 ± 5.38 μg/ml for membranes with and without HA respectively. In addition low pressure and temperature used during production of membranes also allowed greater and more sustained protein release. HA-PLA composite films also showed marked increased permeability compared to plain PLA films, for example after 24 h PLA only films 3.64 ± 1.01 μg/ml, PLA film with 25% HA: 44.99 ± 35.61 μg/ml, PLA film with 75% HA: 153.12 ± 65.57 μg/ml.

Conclusions

The results demonstrate that these composite membranes rapidly absorb protein and that the absorbed protein is released slowly for periods of up to 96 h, dependent on constituents of the material and the manufacturing conditions. Incorporation of HA into these membranes was the key factor for improved protein kinetics and membrane permeability.     

Tissue distribution of RNAs for cystatins, histatins, statherin, and proline-rich salivary proteins in humans and macaques

The tissue distribution of the mRNAs for a number of salivary proteins [proline-rich proteins (PRPs), statherin, cystatins, and the histatins] has been examined in humans and macaques in order to investigate their possible functions and tissue-specific regulation. We have shown that PRP RNAs (0.8-1.5 kb) are expressed in human and rhesus parotid and submandibular glands, and in the human bronchus. The genes for the acidic and basic PRPs are differentially regulated in these tissues. RNAs for acidic PRPs are predominantly expressed in the submandibular gland, for basic PRPs in the respiratory tract, and for both acidic and basic PRPs in the parotid gland. Protein studies of secretions from these tissues confirm the RNA results. Statherin RNA (0.65 kb) was detected in human and rhesus parotid and submandibular glands and the human bronchus, as well as in rhesus lacrimal glands. Statherin was found by tissue immunoperoxidase staining in the serous cells of respiratory tract submucosal glands, which is the same location for the synthesis of PRPs. Several cystatin RNAs (0.8-1.3 kb) were differentially expressed in human parotid glands, submandibular glands, and the bronchus, and in lacrimal glands from both rhesus and cynomolgus macaques. RNAs (0.6 kb) for the histatins were found only in parotid and submandibular glands. Thus, it appears that PRPs, statherin, and cystatins may play a broader role in the physiology of biological fluids and secretions than previously suspected, since they are found in secretions other than saliva. However, the functions of the histatins are restricted to saliva. These studies also pose some interesting questions regarding the differential expression of these genes in a variety of secretory tissues.