Efficacy of three different irrigation techniques in the removal of smear layer and organic debris from root canal wall: a scanning electron microscope study

AimAim of this study was to compare the removal of smear layer and organic debris within the tooth canal among conventional needle irrigation, EndoVac and Endoactivator.MethodologyEighty single-rooted extracted human teeth were prepared with rotary NiTi instrumentation and randomly separated into 4 groups. Twenty teeth were used as positive control (Group 1), irrigated with only saline. Teeth assigned to Group 2 (n = 20) received irrigation with a conventional syringe and a 30-gauge needle (NaviTip, Ultradent, South Jordan, UT); samples in Group 3 (n = 20) were rinsed with an irrigation device based on apical negative pressure (EndoVac, Discus Dental, Culver City, CA) and teeth in Group 4 (n = 20) were treated with a sonic irrigation system (EndoActivator, Dentsply Tulsa Dental, Tulsa, OK, USA). The amount of residual smear layer and debris was evaluated under a scanning electron microscope, and a semi-quantitative score was assigned to each root at the coronal, middle and apical thirds; the chi-square test was used to compare the results of the S.E.M. analysis.ResultsEndoActivator performed the best cleansing for both smear layer and organic debris in all root canal thirds, followed by EndoVac and conventional irrigation (p > 0.001). EndoVac and conventional irrigation showed better cleaning in the coronal area, whereas EndoActivator performed an homogeneous cleansing at all levels.ConclusionsThe EndoVac system and the EndoActivator system demonstrated significantly more efficacy in cleansing root canal walls than conventional needle irrigation.     

The effect of Morinda Citrifolia juice as an endodontic irrigant on smear layer and microhardness of root canal dentin

PurposeThe purpose of this study was to evaluate the effect of Morinda Citrifolia Juice (MCJ) on smear layer removal and microhardness value of root canal dentin in compared with various endodontic irrigants.Material and methodsEighty-four single-rooted human teeth were prepared to apical size of #35. Since decoronation, samples were divided into seven groups of 12 in each (n = 12). Specimens were finally irrigated by either 1: 2.5% NaOCl, 2: 6% MCJ, followed by a final flush of 17% ethylene diaminetetraacetic acid (EDTA), 3: 6% MCJ, 4: 2.5% NaOCl then17% EDTA, 5: MTAD, 6: 2% chlorhexidine (CHX), and 7: saline. After irrigation, all samples were subjected to Vickers microhardness test at 100 and 500-μm depths and then were examined under scanning electron microscopy (SEM) and ImageJ program was used to calculate open dentinal tubules. One way ANOVA and post hoc Tukey tests were used to reveal any significant differences among and between groups respectively.ResultsThe microhardness values at 100 μm and 500 μm for MTAD were significantly lower than for NaOCl + EDTA and MCJ + EDTA groups (p < 0.05). MCJ + EDTA, NaOCl + EDTA, and MTAD protocol significantly removed smear layer in compared with control group (p < 0.05), with no significant differences among these three groups.ConclusionsIt was concluded that 6% MCJ followed by a final flush of 17% EDTA can be regarded as an effective solution on smear layer removal without any adverse influence on microhardness property of root canal dentin.     

Effectiveness of Salvadora persica extracts against common oral pathogens

Objective

The purpose of this study was to evaluate the antibacterial activity of ethanol and hexane extracts of Salvadora persica against common oral pathogens.

Middle mesial canals in mandibular first molars: A micro-CT study in different populations

ObjectiveTo describe the morphological aspects of middle mesial canals (MMC) in mandibular first molars using micro-CT.DesignMandibular first molars collected from the Brazilian (n = 136) and Turkish (n = 122) populations were scanned (voxel size: 9.9 μm) and mesial roots with MMC (n = 48) evaluated regarding several morphological aspects. The incidence of MMC in each population was statistically compared using Chi-square test (α = 0.05).ResultsOverall, the incidence of MMC was 18.6% (48 out of 258 molars) and was significantly higher in the Brazilian (n = 30; 22.1%) than in the Turkish (n = 18; 14.8%) population (p < 0.05). In both populations, confluent configuration of the MMC was the most frequent anatomy. Most of the specimens with MMC had 3 independent orifices (n = 26; 54.2%) and 3 apical foramina (n = 21; 43.8%). The mean minor diameter of the MMC orifice (0.16 mm) was 3 times less than the other orifices (∼0.50 mm). In mesial roots with independent configuration (n = 3; 6.3%), the mean volumes (mm³) of the MMC, mesiobuccal (MBC) and mesiolingual (MLC) canals were 0.20 ± 0.10, 0.75 ± 0.28, and 0.88 ± 0.19, respectively. In the specimens with canal confluence (n = 26; 54.2%), MMC merged to the MBC (n = 8; 16.7%), MLC (n = 4; 8.3%), or to both MBC and MLC (n = 14; 29.2%). Double mesial canal was observed in only 1 specimen. MMC with an independent foramen was observed mostly in Brazilian specimens.ConclusionsIncidence of MMC was higher in the Brazilian molars. Confluent configuration was the most prevalent anatomic variation, while independent and fin configurations, as well as, double MMC, were found only in a few specimens.     

Effects of light penetration and smear layer removal on adhesion of post–cores to root canal dentin by self-etching adhesives

ObjectivesThis study investigated the effects of light penetration and removal of smear layer on the adhesive properties of self-etching adhesives to root canal dentin when using fiber posts.MethodsAltogether 54 human incisors and premolars were decoronated, and the roots after preparing the post space were randomly assigned into six groups. Three groups were treated with a light-cured self-etching adhesive and the other three with a dual-cured self-etching adhesive. In a further sub-division, the first group was light-cured with an irradiation unit; the second was light-cured with the irradiation unit and a light-guiding attachment; and the third was light-cured with the irradiation unit and the attachment after removing smear layer by EDTA and NaOCl. Then, a glass-fiber post was luted into the post space by a dual-cured composite. After 24 h, an hourglass-shaped specimen was trimmed and subjected to MTBS testing.ResultsUsing the light-guiding attachment and removing the smear layer reduced the incidence of pre-testing failure significantly from 57.1% to 19.0% (p < 0.05) in the light-cured adhesive groups and from 68.3% to 3.2% (p < 0.01) in the dual-cured adhesive groups. The MTBS in different locations within a post space were in the range from 8.9 to 17.5 MPa in the light-cured group and from 11.2 to 17.2 MPa in the dual-cured group.SignificanceBetter light penetration in post spaces and removal of the smear layer are effective in improving the adhesive properties of self-etching adhesives to root canal dentin when using fiber posts.     

Influence of a Brazilian wild green propolis on the enamel mineral loss and Streptococcus mutans’ count in dental biofilm

ObjectiveThis study investigated the anti-demineralizing and antibacterial effects of a propolis ethanolic extract (EEP) against Streptococcus mutans dental biofilm.DesignBlocks of sound bovine enamel (n = 24) were fixed on polystyrene plates. S. mutans inoculum (ATCC 25175) and culture media were added (48 h–37 °C) to form biofilm. Blocks with biofilm received daily treatment (30 μL/1 min), for 5 days, as following: G1 (EEP 33.3%); G2 (chlorhexidine digluconate 0.12%); G3 (ethanol 80%); and G4 (Milli-Q water). G5 and G6 were blocks without biofilm that received only EEP and Milli-Q water, respectively. Final surface hardness was evaluated and the percentage of hardness loss (%HL) was calculated. The EEP extract pH and total solids were determined. S. mutans count was expressed by log₁₀ scale of Colony-Forming Units (CFU/mL). One way ANOVA was used to compare results which differed at a 95% significance level.ResultsG2 presented the lowest average %HL value (68.44% ± 12.98) (p = 0.010), while G4 presented the highest (90.49% ± 5.38%HL) (p = 0.007). G1 showed %HL (84.41% ± 2.77) similar to G3 (87.80% ± 6.89) (p = 0.477). Groups G5 and G6 presented %HL = 16.11% ± 7.92 and 20.55% ± 10.65; respectively (p = 0.952). G1 and G4 differed as regards to S. mutans count: 7.26 ± 0.08 and 8.29 ± 0.17 CFU/mL, respectively (p = 0.001). The lowest bacterial count was observed in chlorhexidine group (G2 = 6.79 ± 0.10 CFU/mL) (p = 0.043). There was no difference between S. mutans count of G3 and G4 (p = 0.435). The EEP showed pH 4.8 and total soluble solids content = 25.9 Brix.ConclusionThe EEP seems to be a potent antibacterial substance against S. mutans dental biofilm, but presented no inhibitory action on the de-remineralization of caries process.     

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.     

Effects of different abutment material and surgical insertion torque on the marginal adaptation of an internal conical interface: An in vitro study

PurposeTo evaluate the marginal adaptation at implant–abutment connection of an implant featuring a conical (45° taper) internal hexagonal abutment with a connection depth of 2.5 mm, comparing the performance of two identical abutments of different material (titanium grade-4 and Co-Cr-alloy).MethodsTwenty implants (3.75 mm × 15 mm) were connected to non-matching abutments (5.5 mm × 10 mm) of two different materials (titanium grade-4: n = 10; Co-Cr-alloy: n = 10). The specimens were separately embedded in epoxylite resin, inside copper cylinders, and submerged without covering the most coronal portion (5 mm) of the fixture. Five specimens per group were stressed simulating a surgical 100 Ncm insertion torque, while the others had no torque simulation. All specimens were subjected to a non-axial static load (100 N) in a universal testing machine, under an angle of 30° with respect to the implant axis. Once 100 N load was reached, low shrinkage self-curing resin was injected inside the cylinders, and load was maintained until complete resin polymerization. Specimens were cut and analyzed with optical and scanning-electron-microscope (SEM) to evaluate the marginal adaptation at the implant–abutment connection. Statistical analysis was performed using one-way ANOVA (p = 0.02).ResultsNone of the 20 samples failed. The implant–abutment connection was able to guarantee a good optical seal; SEM analysis confirmed the absence of microgaps.ConclusionsWithin the limits of this study (small sample size, limited time) the marginal adaptation of the implant–abutment connection was not affected by the abutment material nor by the application of surgical insertion torque.     

Efficacy of dexamethasone with controlled hypotension on intraoperative bleeding,postoperative oedema and ecchymosis in rhinoplasty

PurposeThe aim of this retrospective study was to evaluate the efficacy of dexamethasone with controlled hypotension on intraoperative bleeding and postoperative morbidity in rhinoplasty.Materials and methodsSixty rhinoplasty patients required hump resection and lateral osteotomy were included in this study. The patients were randomized into four groups. In group I (n = 15), a single dose of 10 mg/kg dexamethasone was intravenously administered at the beginning of the operation. In group II (n = 15), the patients were given 2 doses of 10 mg/kg intravenously dexamethasone at the beginning of the operation, and 24 hours after the operation. In group III (n = 15), 3 doses of 10 mg/kg intravenously dexamethasone were given at the beginning of the operation, before osteotomy and 24 hours after the operation. Group IV (n = 15) was assigned as control group and the patients were neither administered dexamethasone nor applied hypotension. All cases in groups I, II and III were operated under controlled hypotension. Systolic arterial pressure was aimed to keep between 65 and 75 mmHg for controlled hypotensive anaesthesia. Controlled hypotension was achieved by a remifentanil infusion of 0.1–0.5 microg/kg/min, following a bolus of 1 microg/kg. Degree of eyelid oedema and periorbital soft-tissue ecchymosis was evaluated separately using a scale of 0–4. Intraoperative blood loss was recorded for each patient. Patients were evaluated at 24 hours and postoperative days 2, 5, 7, and 10.ResultsIn groups I, II and III, intraoperative bleeding was more decreased and the operation time was significantly shorter compared with control group (P < 0.001). Eyelid oedema and periorbital ecchymosis were significantly decreased in groups I, II and III at the following postoperative 7 and 10 days (P < 0.001). There was statistically significant difference between group III and other groups at the postoperative 5 and 7 days in lower eyelid oedema (P < 0.001), upper and lower eyelid ecchymosis (P < 0.001 and 0.004, respectively). There were no postoperative complications with using steroid in any of the groups.ConclusionThree doses of dexamethasone with controlled hypotension considerably reduced postoperative morbidities of rhinoplasty with osteotomy as well as intraoperative bleeding. Thus, in group III receiving 3 doses of steroid, when compared to other groups, more uneventful postoperative period were provided for surgeon and the patients.     

“A comparative evaluation between single noncompression titanium miniplate and three dimensional titanium miniplate in treatment of mandibular angle fracture” – A randomized prospective study

PurposeThe aim of this study was to compare efficacy between the single non-compression titanium miniplate and single three-dimensional titanium miniplate in mandibular angle fracture treatment.Method and materialsA prospective study of 20 patients with mandibular angle fractures. Patients were randomly categorized into two groups with 10 patients in each group. Group-I patients were treated with single 2.0 mm conventional titanium miniplate, Group-II patients were treated with single 2.0 mm three-dimensional titanium miniplate according to Champy's principles. Parameters such as stability of fracture fragments, occlusion, mouth opening, additional fixation required and complications were evaluated at different time intervals.ResultsIn Group-I, about 40% (n = 4) of patients showed unstable fracture fragments on immediate postoperative day whereas in Group-II only 10% (n = 1) of patients with fracture instability. In Group-I, 30% (n = 3) had mild occlusal derangement and 20% (n = 2) had deranged occlusion on immediate postoperative day, where as in Group-II only 20% (n = 2) of patients had mild occlusal derangement. Additional fixation required in 30% (n = 3) of patients in group-I, and 10% (n = 1) in Group-II. 20% (n = 2) of patients in Group-I developed infection. All patients in both the groups had inadequate mouth opening on immediate post operative day, later resumed normal mouth opening. 10% (n = 1) in group-I and 20% (n = 2) of patients in group-II presented with postinjury/preoperative inferior alveolar nerve sensory disturbance with no incidence of postoperative sensory disturbance. None of the patients in both the groups had malunion, nonunion, plate fracture, and loosening of plates and screws.Conclusion3-D titanium miniplates showed more favorable results compared to single conventional titanium miniplate with respect to initial interfragmentary stability and complications.     

Comparison of the accuracy for three dental impression techniques and index: An in vitro study

ObjectivesThis in vitro study compared the dimensional accuracy of stone index (I) and three impression techniques: tapered impression copings (T), squared impression copings (S) and modified squared impression copings (MS) for implant-supported prostheses.MethodsA master cast, with four parallel implant abutment analogs and a passive framework, were fabricated. Vinyl polysiloxane impression material was used for all impressions with two metal stock trays (open and closed tray). Four groups (I, T, S and MS) were tested (n = 5). A metallic framework was seated on each of the casts, one abutment screw was tightened, and the gap between the analog of implant and the framework was measured with a stereomicroscope. The groups’ measurements (80 gap values) were analyzed using software (LeicaQWin – Leica Imaging Systems Ltd.) that received the images of a video camera coupled to a Leica stereomicroscope at 100× magnification. The results were statistically analyzed with Kruskal–Wallis One Way ANOVA on Ranks test followed by Dunn's Method, 0.05.ResultsThe mean values of abutment/framework interface gaps were: Master Cast = 32 μm (SD 2); Group I = 45 μm (SD 3); Group T = 78 μm (SD 25); Group S = 134 μm (SD 30); Group MS = 143 μm (SD 27). No significant difference was detected among Index and Master Cast (P = .05).ConclusionUnder the limitations of this study, it could be suggested that a more accurate working cast is possible using tapered impression copings techniques and stone index.     

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.     

Comparison of the Efficacy of Maleic Acid and Ethylenediaminetetraacetic Acid in Smear Layer Removal from Instrumented Human Root Canal: A Scanning Electron Microscopic Study

IntroductionThe aim of this study was to assess, by scanning electron microscopic (SEM) analysis, the ability of 17% EDTA and 7% maleic acid in the removal of the smear layer from the human root canal system.MethodsEighty single-rooted human anterior teeth were subjected to standardized root canal instrumentation (step-back technique) and were irrigated with 2.5% NaOCl after each instrument. Based on the final irrigating solution used, samples were divided randomly into three groups: (1) the EDTA group: 17% EDTA+ 2.5% NaOCl (n = 30), (2) the maleic acid group: 7% maleic acid + 2.5% NaOCl (n = 30), and (3) the control group: 0.9% saline (n = 20). After final irrigation, teeth were prepared for SEM analysis to evaluate the cleaning of the coronal, middle, and apical thirds of radicular dentin by determining the presence or absence of smear layer. The data was statistically analyzed using the Kruskall-Wallis test.ResultsAt the coronal and middle thirds, there was no significant difference between EDTA and maleic acid. Both were equally efficient in the removal of smear layer. In the apical third, maleic acid showed significantly better smear layer removing ability than EDTA.ConclusionFinal irrigation with 7% maleic acid is more efficient than 17%EDTA in the removal of smear layer from the apical third of the root canal system, which is a crucial area for disinfection.     

A new optical detection method to assess the erosion inhibition by in vitro salivary pellicle layer

ObjectivesApplication of the recently developed optical method based on the monitoring of the specular reflection intensity to study the protective potential of the salivary pellicle layer against early enamel erosion.MethodsThe erosion progression was compared between two treatment groups: enamel samples coated by the 15 h-in vitro-formed salivary pellicle layer (group P, n = 90) and the non-coated enamel surfaces (control group C, n = 90). Different severity of the erosive impact was modelled by the enamel incubation in 1% citric acid (pH = 3.6) for 2, 4, 8, 10 or 15 min. Erosion quantification was performed by the optical method as well as by the microhardness and calcium release analyses.ResultsOptical assessment of the erosion progression showed erosion inhibition by the in vitro salivary pellicle in short term acidic treatments (≤4 min) which was also confirmed by microhardness measurements proving significantly less (p < 0.05) enamel softening in the group P at 2 and 4 min of erosion compared to the group C. SEM images demonstrated less etched enamel interfaces in the group P at short erosion durations as well.ConclusionsMonitoring of the specular reflection intensity can be successfully applied to quantify early erosion progression in comparative studies. In vitro salivary pellicle (2 h) provides erosion inhibition but only in short term acidic exposures.Clinical significanceThe proposed optical technique is a promising tool for the fast and non-invasive erosion quantification in clinical studies.     

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.     

Relationship between the IgA antibody response against Streptococcus mutans GbpB and severity of dental caries in childhood

ObjectiveExplore the associations between the severity of dental caries in childhood, mutans streptococci (MS) levels and IgA antibody response against Streptococcus mutans GbpB. Moreover, other caries-related etiological factors were also investigated.Design36–60 month-old children were grouped into Caries-Free (CF, n = 19), Early Childhood Caries (ECC, n = 17) and Severe Early Childhood Caries (S-ECC, n = 21). Data from socio-economic-cultural status, oral hygiene habits and dietary patterns were obtained from a questionnaire and a food-frequency diary filled out by parents. Saliva was collected from children for microbiological analysis and detection of salivary IgA antibody reactive with S. mutans GbpB in western blot.ResultsS-ECC children had reduced family income compared to those with ECC and CF. There was difference between CF and caries groups (ECC and S-ECC) in MS counts. Positive correlations between salivary IgA antibody response against GbpB and MS counts were found when the entire population was evaluated. When children with high MS counts were compared, S-ECC group showed significantly lower IgA antibody levels to GbpB compared to CF group. This finding was not observed for the ECC group.ConclusionsThis study suggests that children with S-ECC have reduced salivary IgA immune responses to S. mutans GbpB, potentially compromising their ability to modify MS infection and its cariogenic potential. Furthermore, a reduced family income and high levels of MS were also associated with S-ECC.     

The effect of rheumatoid arthritis and functional loading on the structure of the mandibular condyle in a transgenic mouse model: An FTIR study

ObjectiveThe objective of the present study was to investigate the effect of rheumatoid arthritis and functional loading through diet modification on the biochemical properties of the mandibular condyle in a transgenic mouse model and compare with healthy littermates.DesignTwenty three, 4-week old hybrid male mice were used. Eleven were of transgenic line hTNF 197 (Tg 197 – with rheumatoid arthritis – RA) and 12 healthy littermates, both from mixed background CBAxC57BL/6. Four groups of mice were formed. Group 1 [n = 5, RA-hard] included transgenic mice and received ordinary (hard) diet; group 2 [n = 6, RA-soft] included transgenic line and received soft diet; group 3 [n = 6, control-hard] were healthy littermates receiving ordinary (hard) diet and group 4 [n = 6, control-soft] were healthy littermates with soft diet. Experimental period was 28 days. Following sacrifice, the mandibular condyles were subjected to micro-attenuated reflection Fourier transform infrared spectroscopy (micro-ATR FTIR) to reveal collagen/proteoglycan conformation of the condylar cartilage, while resin-embedded and metallographically polished specimens were evaluated through reflection FTIR microscopy to identify mineralization status of the corresponding condylar bone.ResultsThe multivariable analysis revealed significantly lower a-helix to amide I percentage area ratio for the transgenic animals after adjusting for diet (β = −4.29, 95% CIs: −8.52, −0.06; p = 0.04). Mineral phase indices did not differ significantly between RA and control groups regardless the type of diet.ConclusionsInternal derangement of the anatomical structure with denaturation in the collagen structural components of the mandibular condyles of the RA animals was found, while no association with functional loading through diet modification was recorded.     

Five-year survival of 3-unit fiber-reinforced composite fixed partial dentures in the anterior area

ObjectivesThe purpose of this clinical study was to evaluate the long-term outcome of 3-unit anterior fixed partial dentures (FPDs) made of fiber-reinforced resin composite (FRC), and to identify design factors influencing the survival rate.Methods52 patients (26 females, 26 males) received 60 indirectly made FRC FPDs, using pre-impregnated unidirectional glass fibers, requiring manual wetting, as framework material. FPDs were surface (n = 48) or hybrid (n = 12) retained and mainly located in the upper jaw. Hybrid FPDs had a combination of retainers; i.e. crown at one and surface retention at the other abutment tooth. Surface FPDs were either purely adhesively retained (n = 29) or with additional mechanical retention (n = 19). Follow-up period was at minimum 5 years, with check-ups every 1–2 years. Six operators were involved, in three centers in the Netherlands, Finland and Sweden. Survival rates, including repairable defects of FPDs, and success rates were determined.ResultsKaplan–Meier survival rate at 5 years was 64% (SE 7%). For the level of success, values were 45% (SE 7%) and the estimated median survival time 58 (SE 10.1) months. For surface FPDs, additional mechanical retention did not improve survival significantly. There was a trend towards better survival of surface FPDs over hybrid FPDs, but differences were not significant. Main failure modes were fracture of the FPD and delamination of veneering composite.SignificanceA success rate of 45% and a survival rate of 64% after 5 years was found. Fracture of the framework and delamination are the most prevalent failure modes, especially for surface FPDs.     

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.     

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.