Effects of Gingival Retraction Paste and Subsequent Cleaning with Hydrogen Peroxide on the Polymerization of Three Elastomeric Impression Materials: An In Vitro Study.

PURPOSE: It has been hypothesized that there are no effects of Expasyl and subsequent cleaning with hydrogen peroxide on polymerization of selected commonly used impression materials. Therefore, the aim of this study was to evaluate the effect of Expasyl paste on the polymerization of three impression materials with and without subsequent cleaning using 3% hydrogen peroxide (H2 O2 ). MATERIALS AND METHODS: Nine standardized stainless steel specimens were fabricated. One hundred and eighty impressions were made using 3 materials (60 each) as follows: group I: poly(vinyl siloxane) (PVS) (Virtual); group II: polyether (Monophase); group III: polyether (Impregum). Groups were subdivided into 3 categories: control without intervention (n = 20), pre-application of Expasyl and subsequent 1-minute washing with water and air-drying (n = 20), and pre-application of Expasyl and subsequent cleaning with 3% H2 O2 for 10 seconds (n = 20). All impressions were made by one operator using auto-mixing cartridges under standardized conditions at room temperature. Evaluation of the polymerization inhibition was blindly and independently performed by three practitioners with comparable experience using a visual scale. The observation was subjectively categorized as noninhibited or inhibited. Data were tabulated and analyzed using Fisher's exact test with significance level set at p ˂ 0.05. RESULTS: Significant differences were found between the control group and the impressions made after contamination with Expasyl (p < 0.001). Polymerization inhibition of PVS and Impregum was similar (in 85% and 90% of the specimens, respectively) when washed with water. There was a statistically significant reduction in polymerization inhibition in both upon cleaning with H2 O2 (p < 0.001); however, polymerization inhibition occurred in 100% of Monophase specimens when contaminated with Expasyl despite the washing technique used. CONCLUSIONS: Under these in vitro conditions, it can be concluded that the remnants of Expasyl on specimens caused a significant polymerization inhibition of the 3 impression materials tested. Subsequent cleaning with 3% H2 O2 significantly reduced this inhibitory effect on polymerization. Expasyl should not be used with Monophase polyether material.

Comparison of clinical and radiographic parameters around short (6 to 8 mm in length) and long (11 mm in length) dental implants placed in patients with and without type 2 diabetes mellitus: 3-year follow-up results.

OBJECTIVE: To compare the clinical and radiographic parameters around short (6 to 8 mm in length) and long (11 mm in length) dental implants placed in patients with and without type 2 diabetes mellitus (T2DM). MATERIAL AND METHODS: Forty-five male patients with T2DM (Group-1) and 42 male non-diabetic controls (Group-2) who had undergone implant therapy in the posterior mandible were included. Depending upon the length of the implant, patients were divided into two subgroups: (a) patients with short implants (6-8 mm long) and (b) patients with long implants (11 mm long). Peri-implant plaque index (PI), bleeding on probing (BOP), probing depth (PD) and crestal bone loss (CBL) were measured at 18 and 36 months of follow-up in both groups. Hemoglobin A1c (HbA1c) levels were measured at baseline and after 18 and 36 months of follow-up in both groups. P-values less than 0.05 were considered statistically significant. RESULTS: The mean age of patients in groups 1 and 2 was 42.5 and 40.6 years, respectively. The mean HbA1c levels at baseline among patients in groups 1 and 2 were 7.7% and 4.5%, respectively. At 18 and 36 months of follow-up, the mean HbA1c levels among patients in groups 1 and 2 were 6.6% and 4.5% and 6.5% and 4.4%, respectively. The mean duration of T2DM among patients that received short and long implants was 4.3 years and 4.1 years, respectively. There was no significant difference in PI, BOP, PD and CBL around implants placed in both groups at 18 and 36 months of follow-up. Success rate of short and long dental implants was 100% in both groups. CONCLUSION: Short implants can demonstrate clinical and radiographic stability in a manner similar to conventional long implants in patients with and without T2DM. The role of oral hygiene and glycemic maintenance in this scenario cannot be disregarded.

Soft tissue changes and crestal bone loss around platform-switched implants placed at crestal and subcrestal levels: 36-month results from a prospective split-mouth clinical trial.

OBJECTIVE: The aim of the present 36-month prospective split-mouth clinical trial was to investigate the peri-implant soft tissue changes and crestal bone loss (CBL) around delayed loaded platform-switched implants placed at crestal and subcrestal levels. MATERIAL AND METHODS: Twenty-three individuals with bilaterally missing either mandibular first or second molars were included. The test and control sites were defined as follows: (i) test sites: implants placed 2 mm below the alveolar crest (subcrestal); (ii) control sites: implants placed at bone level (crestal). Forty-six implants (23 implants in test sites and 23 in control sites) were placed in the center of the healed alveolar ridge in the posterior mandible. Peri-implant bleeding on probing (BOP), probing depth (PD ≥ 4 mm), and CBL was compared at 6, 18, and 36 months of follow-up. P < 0.05 was considered statistically significant. RESULTS: Sixteen males and seven females with a mean age of 43.5 years (29-50) were included. In the control group (n = 23), the highest mean percentage of sites that showed BOP and PD ≥ 4 mm were at 6 months (7.4% and 1.4%, respectively). In the test group (n = 23), the highest mean percentage of sites that showed BOP and PD ≥ 4 mm were at 6 months (2.4% and 1.2%, respectively). The total amount of CBL around crestal and subcrestal implants after 36 months of loading was 0.45 ± 0.2 and 0.3 ± 0.2 mm, respectively. At all follow-up intervals, all intragroup and intergroup comparisons showed no significant differences in BOP, PD ≥ 4 mm, and CBL around implants placed at crestal and subcrestal levels. CONCLUSION: Up to 36 months of follow-up, soft tissue parameters and crestal bone levels can remain equally stable around dental implants placed at crestal and subcrestal levels. The need for long-term follow-up clinical trials is also emphasized.

Efficacy of surgical periodontal treatment with and without photobiomodulation in the treatment of severe periodontitis: An evaluation of periodontal, microbiological, and cytokine levels.

AIM: To compare the efficacy of surgical periodontal treatment (SPT) alone and PDT-assisted surgery in participants with severe periodontitis. MATERIAL AND METHODS: The present clinical trial was completed by 64 participants (n = 32 each). The selection was made according to predefined inclusion and exclusion criteria. Patients in group A were treated with SPT only and participants in group B were treated with SPT adjunct to PDT. Microbiological assessment of P.Gingivalis; T. Forsythia and T.Denticola were evaluated using cultural analysis and periodontal parameters plaque score (PSc), bleeding on probing (BoP) periodontal depth (PD), and clinical attachment loss (CAL) at baseline and post-treatment at 6 months and 12 months were performed. The gingival crevicular fluid (GCF) was collected for the estimation of IL-1ß and tumor necrosis factor-alpha (TNF-α) using an enzyme-linked immunosorbent assay (ELISA). For intra-group comparison and post hoc correction, Student's t-test along with Bonferroni was used. For the difference between follow-ups, an analysis of variance (ANOVA) multiple rank tests were incorporated. RESULTS: The mean age of participants in the SPT group was 55.25±4.6yrs. Whereas, participants treated with PDT adjunct to SPT were 54.88±3.6yrs. Periodontal parameters (BoP, PD, PSc, CAL) showed no significant difference at baseline. At 6 months and 12 months follow-up, a significant difference in all parameters (BoP, PD, PSc, and CAL) was found in participants treated with SPT alone and PDT adjunct to SPT (p<0.05). Inflammatory biomarkers at 6-month and 12-month follow-ups, a statistically significant difference in the level of biomarkers (IL-1ß and TNF-α) were observed in both groups from baseline (p<0.05). However, at baseline, no significant difference was noted in both groups (p> 0.05). The microbiological assessment showed a significant drop in the bacterial count in participants treated with both regimes i.e., SPT alone and PDT adjunct to SPT. CONCLUSION: Photodynamic therapy (PDT) adjunct to surgical periodontal treatment (SPT) in severe periodontitis improves microbiological and periodontal parameters and lowers the level of proinflammatory cytokines.

Application of ß-Tricalcium Phosphate in Adhesive Dentin Bonding.

The study aimed at synthesizing ß-tricalcium phosphate (ß-TCP) nanoparticles and comparing the mechanical properties and dentin interaction of two adhesives: experimental adhesive (EA) and EA with 5 wt.% ß-TCP nanoparticles (ß-TCP-5%). These filler nanoparticles were synthesized and then characterized with scanning electron microscopy (SEM) and micro-Raman spectroscopy. The ß-TCP nanoparticles were incorporated in the adhesives to form two groups: gp-1: EA (control) and gp-2: ß-TCP-5%. These adhesives were characterized by SEM, energy-dispersive X-ray (EDX) spectroscopy and were also assessed for their micro-tensile bond strength (µTBS) with (TC) and without thermocycling (NTC). Fourier Transform Infrared (FTIR) spectroscopy was performed to evaluate the degree of conversion (DC) of two adhesives. The ß-TCP filler was seen as irregularly shaped agglomerates on SEM. The micro-Raman spectra revealed characteristic peaks associated with ß-TCP nanoparticles. Both adhesives presented suitable dentin interaction, which was demonstrated by the formation of resin tags of variable depths. The EDX analysis verified the existence of calcium (Ca) and phosphate (P) for the ß-TCP-5% group. The greatest µTBS values were shown by ß-TCP-5% group samples when they were non-thermocycled (NTC) (ß-TCP-5%-NTC: 34.11 ± 3.46) followed by the thermocycled (TC) samples of the same group (ß-TCP-5%-TC: 30.38 ± 3.66), compared with the EA group. Although the DC presented by ß-TCP-5% group was comparable to the EA group, it was still lower. The addition of ß-TCP nanoparticles in the adhesive improved its µTBS and resulted in a suitable dentin interaction, seen in the form of hybrid layer and resin tag formation. Nonetheless, a decreased DC was observed for the ß-TCP-5% adhesive. Future studies probing the effect of different filler concentrations on various properties of the adhesive are warranted.

Effect of phototherapy on dentin bond strength and microleakage when bonded to resin with different conditioning regimes.

AIM: To assess the efficacy of phototherapy on bond strength and microleakage of bulk fill composites in comparison to conventional dentin surface treatments. MATERIALS AND METHODS: Ninety human third molars were divided into 3 groups (n = 30 each) according to surface conditioning treatment. Group 1 (Etch and Bond) EB, group 2 was treated with Er,Cr: YSGG (ECL) and group 3 was treated with a diode laser (DL). Based on the type of bulk fill resin composite, samples were divided into six sub-groups. In sub-group 1, 2 and 3 (n = 15) build-up was done using ZirconCore (ZC) and these subgroups were named as EB-ZC, ECL-ZC and DL-ZC. In subgroup 4,5,6 (n = 15) MulticCore Flow (MC) was used for core build-up and these subgroups were named as EB-MC, ECL-MC, DL-MC. For shear bond strength (SBS) all the samples were exposed to loads using a universal testing machine. Five samples each from all subgroups were immersed in methylene blue dye for 24 h prior to microleakage testing. Data were assessed using analysis of variance and Tukey multiple comparisons test. RESULTS: Among all the groups the lowest bond strength was achieved in DL-ZC [10.45(0.459)]. Similarly, the highest bond strength was attained in EB-MC[17.84(0.925)]. The highest microleakage scores amongst different group was exhibited in DL-ZC [82.45(39.459)] whereas, the lowest microleakage scores were displayed in EB-MC [31.21(15.92)]. CONCLUSION: Phototherapy in the form of Er,Cr:YSGG laser showed comparable adhesive bond outcomes to conventional etch and bond dentin conditioning techniques. Moreover, Multicore bulk fill material showed better bond strength and microleakage scores than zirconium particle infiltrated bulk fill composite in the presence of dentin phototherapy.

Comparison of Peri-Implant Soft Tissue Parameters and Crestal Bone Loss Around Immediately Loaded and Delayed Loaded Implants in Smokers and Non-Smokers: 5-Year Follow-Up Results.

BACKGROUND: The aim of this study is to compare peri-implant soft tissue parameters (plaque index [PI], bleeding on probing [BOP], and probing depth [PD] ≥4 mm) and crestal bone loss (CBL) around immediately loaded (IL) and delayed loaded (DL) implants in smokers and non-smokers. METHODS: Thirty-one patients with IL implants (16 smokers and 15 non-smokers) and 30 patients with DL implants (17 smokers and 13 non-smokers) were included. Personal data regarding age, sex, and duration and daily frequency of smoking were gathered using a questionnaire. Peri-implant PI, BOP, and PD ≥4 mm were recorded, and mesial and distal CBL was measured on standardized digital radiographs. Multiple group comparisons were performed using the Bonferroni post hoc test (P <0.05). RESULTS: All implants replaced mandibular premolars or molars. Mean scores of PI (P <0.05) and PD ≥4 mm (P <0.05) were statistically significantly higher in smokers compared with non-smokers in patients with IL and DL dental implants. The mean score of BOP (P <0.05) was statistically significantly higher in non-smokers compared with smokers in both groups. CBL (P <0.05) was statistically significantly higher in smokers compared with non-smokers in both groups. There was no statistically significant difference in PI, BOP, PD ≥4 mm, and total CBL among smokers with IL and DL implants. CONCLUSIONS: Tobacco smoking enhances peri-implant soft tissue inflammation and CBL around IL and DL implants. Loading protocol did not show a significant effect on peri-implant hard and soft tissue status in healthy smokers and non-smokers.

Shear bond strength between light polymerized hard reline resin and denture base resin subjected to long term water immersion.

STATEMENT OF THE PROBLEM: The effect of long-term water immersion on the shear bond strength between denture base resin and Triad visible-light-polymerized (VLP) direct hard reline resin is not known. PURPOSE: The aim of this study was to investigate the bonding characteristics of Triad VLP direct hard reline resin to heat-polymerized denture base resin subjected to long-term water immersion. MATERIAL AND METHODS: Ninety circular disks, 15 mm in diameter and 3 mm thick, of denture base resin were polymerized from a gypsum mold. Sixty specimens were subjected to water immersion and 30 were stored at ambient room temperature for 4 months. Thirty water-immersed specimens were dried with gauze (group 1), while the other 30 water-immersed specimens were dried with a hair dryer (group 2). The dry specimens (n = 30) represented the control group (group 3). All specimens were air abraded and painted with bonding agent before packing Triad VLP direct hard-reline resin. Specimens in each group were subjected to thermal cycling for 50,000 cycles between 4 °C and 60 °C water baths with 1-min dwell time at each temperature. The bond strength at which the bond failed under stress was recorded using a universal testing machine. One-way ANOVA and Tukey post hoc comparison were applied to find significant differences between groups (α = 0.05). RESULTS: Significant differences in mean shear bond strength among the specimens existed because of variable water content in the denture base resin (P < 0.05). Group 3 (dry) was higher than group 2 (desiccated), and the lowest was group 1 (saturated). CONCLUSION: The shear bond strength of Triad VLP direct hard reline resin to denture base resin depended on the water content in the denture base resin. The dry denture base resin demonstrated superior bond strength compared with the desiccated and water-saturated denture base resins.