Morphological changes produced by acid dissolution in Er:YAG laser irradiated dental enamel

Several scientific reports have shown the effects of Er:YAG laser irradiation on enamel morphology. However, there is lack of information regarding the morphological alterations produced by the acid attack on the irradiated surfaces. The aim of this study was to evaluate the morphological changes produced by acid dissolution in Er:YAG laser irradiated dental enamel. Forty‐eight enamel samples were divided into four groups (n = 12). GI (control); Groups II, III, and IV were irradiated with Er:YAG at 100 mJ (12.7 J/cm²), 200 mJ (25.5 J/cm²), and 300 mJ (38.2 J/cm²), respectively, at 10 Hz without water irrigation. Enamel morphology was evaluated before‐irradiation, after‐irradiation, and after‐acid dissolution, by scanning electron microscopy (SEM). Sample coating was avoided and SEM analysis was performed in a low‐vacuum mode. To facilitate the location of the assessment area, a reference point was marked. Morphological changes produced by acid dissolution of irradiated enamel were observed, specifically on laser‐induced undesired effects. These morphological changes were from mild to severe, depending on the presence of after‐irradiation undesired effects. Microsc. Res. Tech. 77:410–414, 2014. © 2014 Wiley Periodicals, Inc.     

Morphological and chemical changes in human deciduous dentin after phosphoric acid,self‐etching adhesive and Er: YAG laser conditioning

The morphological and chemical changes in deciduous dentin produced by different conditioning protocols were evaluated in this in vitro study. Eighty primary dentin samples were divided into eight groups (n = 10): G1, acid etching; G2, self‐etching adhesive; G3, G4, Er: YAG laser irradiation at 25.5 and 38.2 J cm^?2, respectively; 10 Hz and spray irrigation. Groups 5, 6, 7, and 8 were irradiated at previous densities, and then phosphoric acid or self‐etching adhesive conditioning was applied. Scanning electron microscopy (SEM) and energy dispersive X‐ray spectroscopy (EDS) were used to evaluate chemical and morphological changes. Paired t‐test and One‐way ANOVA were used for statistical analysis (p ≤ 0.05). All samples showed different morphology with specific characteristics according to the conditioning protocol. Changing element concentration values are expressed in atomic percent (at %). After conditioning, there were statistically significant differences (p ≤ 0.05) for p at% and Ca/P in all groups; highlighting the following additional findings by group: G1, G7, and G8 showed changes in all elements studied, G2 presented a decrease in C at% and increased Ca at%, G3 and G4 exhibited at% changes in C, trace elements and Ca. Furthermore, G5 showed at% changes in O and trace elements; while G6 changes were observed on C at%, O at% and trace elements at%. Dentin morphology and chemical composition varied in accordance with the conditioning protocol, with characteristics specific for each one that could have clinical implications for the retention and bond strength performance of adhesive materials.     

Effect of super short pulse Er:YAG laser on human dentin—Scanning electron microscopy analysis

This study evaluated the effect of different pulse widths in the morphological characteristics of human dentin irradiated with Er:YAG in cavity preparation protocols and dentin pretreatment. Dentin discs with 2 mm thickness were obtained from 18 human molars. The experimental groups were composed from two variables: (1) clinical protocol—cavity preparation (E = 200 mJ/20 Hz)—and pretreatment (E = 80 mJ/2 Hz); and (2) pulse duration—50, 300, and 600 μs. This formed six experimental groups (n = 3): G1 (E = 200 mJ/20 Hz/50 μs); G2 (E = 200 mJ/20 Hz/300 μs); G3 (E = 200 mJ/20 Hz/600 μs); G4 (E = 80 mJ/2 Hz/50 μs); G5 (E = 80 mJ/2 Hz/300 μs); G6 (E = 80 mJ/2 Hz/600 μs). The samples were irradiated with the Er:YAG laser by noncontact mode at a focal distance of 7 mm from the target point under continuous water spray (60% water and 40% air). After the irradiation, they were processed for scanning electron microscopy (SEM). Morphological analysis showed an irregular dentin surface, absence of smear layer with opening of the exposure of dentinal tubules and protruding peritubular dentin—without indications of changes for all protocols used. Regardless of the analyzed experimental group, the dentin surface showed a microretentive morphology characteristic of ablation. The G1 and G4 showed a rougher surface when compared to other groups. Finally, we concluded that the pulse width can influence the morphological characteristics of the irradiated dentin tested in different clinical indications. The larger surface irregularity caused by regulation with less pulse width (50 µs) seems more appropriate to get a microretentive pattern necessary for successful adhesives restoration procedures. Microsc. Res. Tech. 78:472–478, 2015. © 2015 Wiley Periodicals, Inc.     

Effect of Er:YAG laser irradiation on deciduous enamel roughness and bacterial adhesion: An in vitro study

Laser irradiation has been proposed as a preventive method against dental caries since it is capable to inhibit enamel demineralization by reducing carbonate and modifying organic matter, yet it can produce significant morphological changes. The purpose of this study was to evaluate the influence of Er:YAG laser irradiation on superficial roughness of deciduous dental enamel and bacterial adhesion. Fifty‐four samples of deciduous enamel were divided into three groups (n = 18 each). G1_control (nonirradiated); G2_100 (7.5 J/cm²) and G3_100 (12.7 J/cm²) were irradiated with Er:YAG laser at 7.5 and 12.7 J/cm², respectively, under water irrigation. Surface roughness was measured before and after irradiation using a profilometer. Afterwards, six samples per group were used to measure bacterial growth by XTT cell viability assay. Adhered bacteria were observed using confocal laser scanning microscopy (CLSM) and a scanning electron microscopy (SEM). Paired t‐, one‐way analysis of variance (ANOVA), Kruskal‐Wallis and pairwise Mann–Whitney U tests were performed to analyze statistical differences (p < .05). Before treatment, samples showed homogenous surface roughness, and after Er:YAG laser irradiation, the surfaces showed a significant increase in roughness values (p < .05). G3_100 (12.7 J/cm²) showed the highest amount of Streptococcus mutans adhered (p < .05). The increase in the roughness of the tooth enamel surfaces was proportional to the energy density used; the increase in surface roughness caused by laser irradiation did not augment the adhesion of Streptococcus sanguinis; only the use of the energy density of 12.7 J/cm² favored significantly the adhesion of S. mutans.     

Influence of Er:YAG laser frequency on dentin caries removal capacity

The purposes of this study were to evaluate in vitro the influence of different frequencies of Er:YAG laser on the human dentin caries removal capacity. Thirty fragments obtained from third molars were randomly assigned into three groups (n = 10) according to the laser frequency used: 4, 6, and 10 Hz. The caries lesion (±1 mm deep) was induced before the irradiation by S.mutans cultures for 6 weeks. The specimens of all groups were irradiated with 200 mJ of energy in noncontact and focused mode under constant refrigeration (water flow: 2.5 mL/min). Quantitative analysis of the caries removal was performed by DIAGNOdent^TM and the Axion Vision^TM software. Qualitative analysis was performed by Scanning electron microscope (SEM) and light microscope (LM). Data were analyzed by ANOVA and Fishers' tests. The DIAGNOdent^TM revealed that the caries removal was similar with 4 and 6 Hz and was superior with 10 Hz (P < 0.05). The analysis with Axion Vision^TM software revealed that the caries removal was similar with 6 and 10 Hz and the 4 Hz group promoted the lowest caries removal. Through SEM morphologic analysis, some specimens irradiated with 4 Hz presented, under the demineralized dentin, a disorganized collagenous matrix. The LM images revealed that all frequencies used promoted irregular caries removal, being observed over preparations with 6 and 10 Hz. It can be concluded that the increase of Er:YAG laser frequency provided a higher dentin caries removal without selectivity to the disorganized dentin. Microsc. Res. Tech., 2010. © 2010 Wiley‐Liss, Inc.     

Microtensile strength of resin cement bond to indirect composite treated by different output powers of Er:YAG laser

The study aimed to evaluate the effect of different output powers of Er:YAG laser on microtensile bonding strength of indirect composite to resin cements.36 indirect composite blocks (GC Gradia DA2, Japan) size 15 × 10 × 10 mm³ were constructed, and divided into 12 groups, as follows:G1: control group (no treatment); Groups G2 to G6: treated with Er:YAG laser (2,940 nm) in noncontact mode, frequency 20 Hz, pulse duration 470 µs, with output power ranging from 2W to 6W; Groups G7 sandblasting, Groups 8 to G12: as Groups G2 to G 6 with preparatory sandblasting. One specimen from each group was analyzed by SEM; each specimen was fixed to a specialized metal jig using cyanoacrylate (Mitreapel, Beta Kimya San. Ve TIC, Iran) and debonded under tension with a universal testing machine (Zwick, Germany) at a crosshead speed of 0.5 mm min^?1. Sandblasting and laser can improve bond strength above an energy level of 150 mJ. SEM evaluation of laser‐treated specimens showed irregularities and deep undercuts. T test analysis showed no significant difference between sandblasted and non‐sandblasted group, with laser output power of 0, 100, or 150 mJ (P = 0.666, P = 0.875, and P = 0.069); in the specimens irradiated with energy output of 200, 250, or 300 mJ, sandblasted specimens showed higher bond strength than non‐sandblasted ones. The results demonstrate that, in composite resin irradiated with laser at energy output of 200–300 mJ, sandblasting might be a suitable procedure to enhance bond strength of resin cement. Microsc. Res. Tech. 79:328–333, 2016. © 2016 Wiley Periodicals, Inc.     

Resin luting materials: Tissue response in dog's teeth

The aim of this study was to evaluate radiographically and histologically the pulpal and periapical response to self‐adhesive (Rely X? Unicem) and self‐etching and self‐curing (Multilink^®) resin‐based luting materials in deep cavities in dogs' teeth. Deep class V cavities (0.5‐mm–thick dentin) were prepared in 60 canine premolars and the following materials were applied on cavity floor: Groups I/V—RelyX? Unicem; Groups II/VI—Multilink^®; Groups III/VII—zinc phosphate cement (control) and; Groups IV/VIII—gutta‐percha (control). Cavities were restored with silver amalgam. Animals were euthanized after 10 days (groups I–IV) and 90 days (groups V–VIII). Tooth/bone blocks were radiographed and processed for histopathological evaluation of pulp and periapical tissue response to the materials. All materials presented similar histopathological features and radiographic findings at both periods. The pulp tissue was intact. The apical and periapical regions and periodontal ligament thickness were normal. No inflammatory cells, resorption of mineralized tissue (dentin, cementum, and alveolar bone) or bacteria were observed. The lamina dura was intact and no areas of periapical bone rarefaction or internal/external root resorption were observed radiographically. It can be concluded that Rely X? Unicem and Multilink^® caused no adverse tissue reactions and may be indicated for cementation of indirect restorations in deep dentin cavities without pulp exposure. Microsc. Res. Tech. 78:1098–1103, 2015. © 2015 Wiley Periodicals, Inc.     

Comparative effects of two different doses of low‐level laser therapy on wound healing third‐degree burns in rats

Burns are injuries caused by direct or indirect contact to chemical, physical, or biological agents. Low‐level laser therapy (LLLT) is a promising treatment since it is low‐cost, non‐invasive, and induces cell proliferation. This study aimed to investigate the effects of LLLT (660 nm) at two different fluences (12.5 J/cm² and 25 J/cm²) per point of application on third‐degree burns in rats. Thirty rats (Wistar) divided into GC, GL12.5, and GL25 were used in the study, and submitted to burn injury through a soldering iron at 150°C, pressed on their back for 10 s. LLLT was applied immediately, and 2, 4, 6, and 8 days after wound induction. Histological analysis revealed a decreased inflammatory infiltrate in the group treated with 25 J/cm², and intense inflammatory infiltrate in the control group and in the group treated with 12.5 J/cm². The immunostaining of COX‐2 was more intense in the control groups and in the group treated with 12.5 J/cm² than in the group treated with 25 J/cm². Conversely, VEGF immunomarking was more expressive in the group treated with 25 J/cm² than it was in the other two groups. Therefore, our findings suggest that the use of 25 J/cm² and 1 J of energy was more effective in stimulating the cellular processes involved in tissue repair on third‐degree burns in rats by reducing the inflammatory phase, and stimulating angiogenesis, thus restoring the local microcirculation which is essential for cell migration. Microsc. Res. Tech. 79:313–320, 2016. © 2016 Wiley Periodicals, Inc.     

Erosion effects on chemical composition and morphology of dental materials and root dentin

Purpose: This work aims to study the erosion on restorative materials and on surrounding dentin. Fifty root dentin samples were obtained from bovine incisors. Methods: Twenty samples were not restored and thirty received cavity preparations. Samples were assigned to five groups: G1, G2: sound dentin (D); G3: composite resin (CR); G4: resin‐modified glass‐ionomer cement (RMGIC); G5: glass‐ionomer cement (GIC). The samples of groups 2–5 were submitted to six cycles (demineralization–remineralization). Samples were analyzed by micro energy‐dispersive X‐ray fluorescence spectrometry (μ‐EDXRF) and by scanning electron microscopy (SEM). Results: Mineral loss was greater in G2 samples than in RMGI > CR > GIC > D (control). SEM images showed pronounced dentin demineralization in groups 2 and 4. The acid erosion has a significant effect on mineral loss (Ca and P) of root dentin without restoration. Conclusions: Composite resin had the best chemical resistance to erosion among all the materials. Fluoride contained in GIC seemed to cause some protection, however, with material degradation. Chemical interaction of tooth‐colored dental materials with root dentin could be assessed by μ‐EDXRF. Microsc. Res. Tech. 75:703–710, 2012. © 2011 Wiley Periodicals, Inc.     

Surface change of root canal dentin after the use of irrigation activation protocols: Electron microscopy and an energy‐dispersive X‐ray microanalysis

This study evaluated the mineral contents of root‐canal dentin after treatment with different irrigation activation protocols. One hundred and eight maxillary lateral incisor teeth were randomly divided into eight experimental groups and one control group. Root canals were prepared using ProTaper rotary files, with the exception of the Self‐Adjusting File (SAF) group. Canals were irrigated with 2 mL of 5% sodium hypochlorite (NaOCl) at each instrument change, and received a final flush with 10 mL of 17% ethylenediaminetetraacetic acid (EDTA) and 10 mL of 5% NaOCl for 1 min. The control group was irrigated with distilled water. Group I (GI): Needle syringe irrigation; Group II (GII): NaviTip FX; Group III (GIII): CanalBrush; Group IV (GIV): Manual dynamic activation with gutta‐percha; Group V (GV): Passive ultrasonic irrigation; Group VI (GVI): EndoActivator; Group VII (GVII): EndoVac; Group VIII (GVIII): SAF. The level of elemental composition was analyzed by a scanning electron microscopy and an energy‐dispersive spectrometer (EDS) system. The results were then statistically analyzed by one‐way ANOVA and Tukey tests. Ca/P ratio was changed after treatment with SAF and EndoActivator. The Ca, P, Mg, and S level changes were not statistically significant (P > 0.05). Final irrigation activation protocols did not alter the mineral level of root dentin surface. Microsc. Res. Tech. 76:893–896, 2013. © 2013 Wiley Periodicals, Inc.     

Effects of Er,Cr:YSGG laser parameters on dentin bond strength and interface morphology

Previous studies have shown the effects of Er,Cr:YSGG laser irradiation on the dentin bond strength; but there are few reports that show the significance of the irradiation with different laser parameters on dentin bond strength and interface morphology. This in‐vitro study attempted to evaluate the microtensile bond strength (μTBS) and interface morphology of resin‐dentin interfaces, either followed by treatment with Er,Cr:YSGG laser irradiation with different parameters or not. The flattened dentin samples of 35 bovine teeth were embedded into acrylic blocks and randomly divided into seven groups according to surface treatments using Er,Cr:YSGG lasers with different parameters: 3 W/20 Hz, 3 W/35 Hz, 3 W/50 Hz, 1.5 W/20 Hz, 1.5 W/35 Hz, 1.5 W/50 Hz, or no laser treatment (n = 5). Composite buildups were done over bonded surfaces and stored in water (24 hours at 37°C). Specimens were sectioned into sticks that were subjected to μTBS testing and observed under FE‐SEM. Control groups (27.70 ± 7.0) showed statistically higher values than laser‐irradiated groups. There were no significant differences among laser groups. Despite that, increasing the pulse frequency yielded slightly higher bond strength. Depending on laser settings, Er,Cr:YSGG laser irradiation caused interfacial gaps and resin tags with wings morphology. With the parameters used in this study, Er,Cr:YSGG laser irradiation promoted morphological changes within resin‐dentin interfaces and negatively influenced the bond strength of adhesive systems. Microsc. Res. Tech. 78:1104–1111, 2015. © 2015 Wiley Periodicals, Inc.     

Calcium hypochlorite as a dentin deproteinization agent: Microleakage,scanning electron microscopy and elemental analysis

Purpose: This study investigated the influence of collagen removal with calcium hypochlorite on the surface morphology of acid‐etched dentin and on the microleakage of composite restorations. In addition, the elemental composition (EC) of dentin after removal of the collagen fibrils was analyzed. Materials and Methods: Forty third molars received two cavities and were divided into four groups according to dentin treatment: CTRL—no pre‐treatment; Na10—10% NaOCl for 30 s; Ca10—10% CaOCl for 30 s, and Ca15—15% CaOCl for 30 s. The cavities were filled using an acetone‐based adhesive system and a resin composite; they were then subjected to thermal cycling for 5,000 cycles, immersed in methylene blue for 4 h and sectioned into 1‐mm thick slabs. Two examiners evaluated two slices per tooth using a stereomicroscope and assigned the degree of infiltration (scores 0–3). The data were analyzed using the Kruskal–Wallis (α = 0.05). Four teeth received surface treatment according to the groups and were submitted to SEM and EDS to carry at the EC. Results: There was no significant difference between the experimental groups (P = 0.533). CaOCl alters the morphology and surface composition of the dentin, resulting in an increase in the amount of calcium in the interface. Conclusions: When used prior to an acetone‐based adhesive system, CaOCl did not produce any differences in microleakage when compared to the CTRL group or to the Na10 group. Microsc. Res. Tech. 78:676–681, 2015. © 2015 Wiley Periodicals, Inc.     

Effects of chemical agents on physical properties and structure of primary pulp chamber dentin

This study evaluated the effects of chemical agents on the physical properties and structure of primary pulp chamber dentin using surface roughness, microhardness tests, and scanning electron microscopy (SEM). Twenty‐five primary teeth were sectioned exposing the pulp chamber and were divided into five groups (n = 5): NT, no treatment; SH1, 1% sodium hypochlorite (NaOCl); SH1U, 1% NaOCl + Endo‐PTC^®; SH1E, 1% NaOCl + 17% EDTA; and E, 17% EDTA. After dentin treatment, the specimens were submitted to roughness, microhardness testing, and SEM analysis. Roughness and microhardness data were submitted to one‐way ANOVA and Tukey's test (P < 0.05). The SH1E group showed the highest roughness, followed by the E group (P < 0.05) when compared with the NT, SH1, and SH1U groups. Microhardness values of SH1 and SH1U showed no significant difference as compared to the NT (control) group (P > 0.05). Microhardness values could not be obtained in the EDTA groups (SH1E and E). The presence of intertubular dentin with opened dentin tubules was observed in the NT, SH1, and SH1U groups. SH1E showed eroded and disorganized dentin with few opened tubules and the intertubular/peritubular dentin was partially removed. Considering the physical and structural approaches and the chemical agents studied, it can be concluded that NaOCl and NaOCl associated with Endo‐PTC^® were the agents that promoted the smallest changes in surface roughness, microhardness, and structure of the pulp chamber dentin of primary teeth. Microsc. Res. Tech. 77:52–56, 2014. © 2013 Wiley Periodicals, Inc.     

The use of an Er:YAG laser to remove demineralized dentin and its influence on dentin permeability

The purpose of this study was to analyze, correlate, and compare the demineralization and permeability of dentin remaining after caries removal with either an Er:YAG laser, a bur, or a curette. Thirty human dentin fragments were immersed in a demineralizing solution for 20 days and were randomly divided into three groups (n = 10) for the removal of the demineralized lesion. The groups were G1—Er:YAG laser (200 mJ/6 Hz; noncontact at 12 mm; spot: 0.63 mm), G2—Bur, and G3—Curette. The specimens were then immersed in a 10% copper sulfate solution, then in a 1% dithiooxamide alcoholic solution for 30 min and kept in ammonia vapor for 7 days. Next, the specimens were examined with optical microscopy. The amount of demineralized dentin and the level of copper ion infiltration in the dentin were quantified in μm using Axion Vision software. Data were analyzed with the Kruskal‐Wallis test (p < 0.05) and Pearson's Correlation test. The analysis revealed no significant differences between the three caries removal methods in terms of their capacity to remove demineralized tissue (G1: 10.6 μm; G2: 8.4 μm; G3: 11 μm), although the laser removal generated more tissue permeability than the others methods (G1: 17.6 μm; G2: 6.6 μm; G3: 5.5 μm). The correlation between the remaining demineralized dentin and the dentin permeability was moderate for the conventional methods and higher for the Er:YAG laser. It can therefore be concluded that the laser produced an increase in permeability that was directly proportional to the amount of demineralized tissue removal. Microsc. Res. Tech. 76:225–230, 2013. © 2012 Wiley Periodicals, Inc.     

Dentin bond strength and nanoleakage of the adhesive interface after intracoronal bleaching

This study evaluated dentin bond strength (BS) and nanoleakage of non‐ and pre‐etched dentin immediately (T₀,), 7 days (T₇), and 14 days (T₁₄) after bleaching. Bovine incisors (150) were selected and half of them submitted to intrapulpal dentin etching (e). Non‐ and pre‐etched dentin were subjected to the following (n = 15): no bleaching/control (C); 35% carbamide peroxide (CP); 35% hydrogen peroxide (35% HP); 25% hydrogen peroxide (25% HP); and sodium perborate (SP). Bleaching agents were applied to the pulp chamber four times within a 72‐h interval. Afterwards, pulp chamber dentin was prepared for the BS test at different evaluation times (n = 5): T₀, T₇, and T₁₄. Composite blocks were built on pulp chamber and sectioned in slices. Slices were reduced to an hour‐glass shape with a cross‐sectional area of 0.8 mm² and submitted to microtensile BS test. Two additional specimens for each group were prepared for nanoleakage evaluation by transmission electron microscopy (TEM). Results were analyzed by ANOVA (two‐way) and Dunnett's test (p < .05). BS decreased immediately after intracoronal bleaching for both sound and pre‐etched dentin (p < .05). At T₁₄, the BS of non‐etched bleached dentin increased for all groups, whereas the pre‐etched SPe group presented BS similar to the Ce. Nanoleakage within the hybrid layer was perceptible immediately after bleaching, although a decrease in nanoleakage was observed for all groups at T₁₄. Adhesive restorations should be performed 7–14 days after bleaching, according to the bleaching agent used. Intracoronal bleaching should be performed preferably with sodium perborate if previous dentin etching is applied.     

Micro‐shear bond strength of adhesives with different degrees of acidity: Effect on sound and artificially hypermineralized dentin

This study evaluates the bond strength of four self‐etching adhesive systems with different acidity levels in normal and artificially hypermineralized dentin substrate. Healthy human molars were divided into groups: normal dentin—N (n = 36) and artificially hypermineralized dentin—H (n = 36). Self‐etching adhesive systems Clearfil S³ Bond (n = 9), Optibond All in One (n = 9), Clearfil SE Bond (n = 9), and Adhese (n = 9) were used for both the N and H groups. Transparent cylindrical matrices were positioned on the treated dentin surfaces, filled with composite resin, and light‐cured for 40 s. After the transparent cylindrical matrices were removed, the specimens were stored for 24 hr in a humid environment at 37°C and were subjected to a micro‐shear bond strength test. For each group, a specimen was prepared and evaluated in scanning electron microscope for adhesive interface observation. Normality was confirmed and the two‐way analysis of variance and Games–Howell post‐tests were conducted (α = .05). The data demonstrated an interaction between the adhesive system and type of dentin substrate (p < .01). For normal dentin, all adhesive systems assessed were adequate; however, in the hypermineralized dentin, the Clearfil SE Bond two‐step self‐etching adhesive system with mild pH presented the highest immediate bond strength. There was a predominance of adhesive failures for all adhesive systems in the different dentin substrates evaluated. It was concluded that the self‐etching adhesive systems evaluated were efficient for both substrates, and for the hypermineralized dentin, the Clearfil SE Bond presented a higher bond strength value.     

Effect of low-level laser therapy on intramembranous and endochondral autogenous bone grafts healing

The aim of this study was to evaluate the healing process of intramembranous (IM) and endochondral (EC) bone grafts under low‐level laser therapy (LLLT). Male rabbits underwent onlay autogenous bone grafts (1 cm in diameter) retrieved from the calvaria and iliac crest and fixed on parietal bones, divided into four groups: Calvaria (C), Iliac (I), Calvaria + LLLT (C+L), and Iliac + LLLT (I+L). Animals from C+L and I+L Groups had their grafts exposed to LLLT (AlGaAs–808 nm, CW, 30 mW, 0.028 cm² average laser beam area), 15 s irradiation time (16 J/cm² per point–total of 64 J/cm² per session). After 7, 14, 30, and 60 days, grafts were retrieved and resorption pattern analyzed by means of morphometry and TRAP‐positive osteoclasts detection. Differences in the resorption levels of iliac grafts were observed, presenting 40% in I group against 8% in I+L grafts at the 14th day of evaluation (P < 0.05). After 30 days, resorption was maintained at 41% in I group, whereas I+L presented 15% in the same period (P = 0.0591). No significant differences were noted in the rates of calvaria grafts resorption in all periods. A significant higher number of osteoclasts on the grafts' surface was observed in C+L Group at day 30, in comparison with C group. In I+L Group, prevalence of osteoclasts was marked at day 7 (P < 0.05) in comparison to I Group. In general, it was concluded that biomodulative effects of LLLT did not significantly affect healing and resorption processes of autogenous bone grafts from EC and IM origins. Microsc. Res. Tech. 75:1237–1244, 2012. © 2012 Wiley Periodicals, Inc.     

Resin-tooth interfacial morphology and sealing ability of one-step self-etch adhesives: microleakage and SEM study

OBJECTIVES: To compare microleakage of three self‐etch adhesives and to analyze enamel surface morphology and interfacial morphology of resin–enamel and resin–dentin interface under scanning electron microscope (SEM). EXPERIMENTAL DESIGN: Study was conducted in 65 extracted human premolars. Class V cavities were prepared in 45 teeth and assigned to three groups (n = 15) according to three self‐etch adhesives (OptiBond All‐in‐One, iBond, and Adper Prompt L‐Pop). After restoration, 10 samples from each group were used to assess microleakage at enamel and dentin margin. Five samples from each group were used for analysis of interfacial morphology at resin–enamel and resin–dentin interface under SEM. Remaining 20 teeth were used to prepare flat enamel buccal surfaces to analyze the difference in surface morphology after treatment with three adhesives (n = 5 each) and 36% phosphoric acid treatment (n = 5). PRINCIPAL OBSERVATIONS: At enamel margin, Prompt L‐Pop depicted least leakage of all the three adhesives and also showed best interfacial adaptation under SEM. At dentin margin, OptiBond All‐in‐One showed significant less leakage than iBond and Prompt L‐Pop. On flat enamel surface, phosphoric acid produced the most retentive etching pattern when compared with the three adhesives. CONCLUSION: Prompt L‐Pop showed the best bonding effectiveness in enamel, whereas OptiBond All‐in‐One performed significantly better in dentin. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.     

Influence of chlorhexidine on dentin adhesive interface micromorphology and nanoleakage expression of resin cements

This study focused on adhesive interface morphologic characterization and nanoleakage expression of resin cements bonded to human dentin pretreated with 1% chlorhexidine (CHX). Thirty‐two non‐carious human third molars were ground flat to expose superficial dentin. Resin composite blocks were luted to the exposed dentin using one conventional (RelyX ARC) and one self‐adhesive resin cement (RelyX U100), with/without CHX pretreatment. Four groups (n = 8) were obtained: control groups (ARC and U100); experimental groups (ARC/CHX and U100/CHX) were pretreated with 1% CHX prior to the luting process. After storage in water for 24 h, the bonded teeth were sectioned into 0.9 × 0.9 mm² sticks producing a minimum of 12 sticks per tooth. Four sticks from each tooth were prepared for hybrid layer evaluation by scanning electron microscope analysis. The remaining sticks were immersed in silver nitrate for 24 h for either nanoleakage evaluation along the bonded interfaces or after rupture. Nanoleakage samples were carbon coated and examined using backscattered electron mode. Well‐established hybrid layers were observed in the groups luted with RelyX ARC. Nanoleakage evaluation revealed increase nanoleakage in groups treated with CHX for both resin cements. Group U100/CHX exhibited the most pronouncing nanoleakage expression along with porous zones adjacent to the CHX pretreated dentin. The results suggest a possible incompatibility between CHX and RelyX U100 that raises the concern that the use of CHX with self‐adhesive cements may adversely affect resin‐dentin bond. Microsc. Res. Tech. 76:788–794, 2013. © 2013 Wiley Periodicals, Inc.