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Biomedical subjects

Franklin García-Godoy

Publications and source records attributed to Franklin García-Godoy.

At least 19 recordsLinked to original sources
PubMed2006

Sorption and solubility testing of orthodontic bonding cements in different solutions.

To evaluate and compare the solubility and sorption of orthodontic bonding cements after immersion in different solutions, five different cements were used: a fluoride-containing resin composite, a light-cured glass ionomer cement, a light-cured resin composite, a paste-paste chemically cured resin composite, and a liquid-paste chemically cured resin composite. Five different solutions were employed: distilled water, artificial saliva, an alcohol-free mouthrinse solution (Orthokin), a 5% alcohol mouthrinse solution (Perioaid), and a 75% ethanol/water solution. Five disc specimens (15 mm x 0.85 mm) were used for each experimental condition. Materials were handled following manufacturers' instructions and were ground wet with silicon carbide paper. Solubility and sorption of the materials were calculated by means of weighing the samples before and after immersion and desiccation. Data were analyzed by two-way ANOVA and Student-Newman-Keuls test (p < 0.05). The light-cured glass ionomer cement showed the lowest solubility and the highest sorption values. When using alcohol-containing solutions as storage media, solubility of the paste-paste chemically cured resin composite increased, and sorption values for the tested chemically cured resin composites were also increased. The use of alcohol-free mouthrinses does not affect sorption and solubility of orthodontic cements. The chemically cured (paste-paste) composite resin cement, requiring a mixing procedure, was the most affected by immersion in alcohol-containing solutions.

Absorption↗
PubMed2006

The outlook for implants and endodontics: a review of the tissue engineering strategies to create replacement teeth for patients.

Ideally, root canal therapy involves the removal of diseased pulp tissues and permanent replacement with healthy pulp to revitalize teeth. Rather than placing implants, the ideal solution is to grow new replacement teeth. Success rates of implants and endodontic treatments can exceed 90%, which presents a formidable challenge to tissue engineering researchers to ensure that future dental treatments are even more successful. The purpose of this article is to explain how tissue engineering can be used to create replacement teeth. The science of tissue engineering has evolved from growing simple tissues in cell culture incubators to a multistep process. Although the problems of introducing tissue engineering therapies as part of routine dental treatments are substantial, the potential benefits are equally ground breaking.

Biomimetic Materials↗
PubMed2006

Effects of sonic energy on monospecific biofilms of cariogenic microorganisms.

PURPOSE: To evaluate the in vitro differential effect of sonic energy, delivered by Sonicare Advance, on cariogenic and non-cariogenic bacteria biofilms. METHODS: A wild strain of Streptococcus mutans, Lactobacillus acidophilus, Streptococcus salivarius and Veillonella alcalescens was isolated from human dental plaque. For each of the four microorganisms a biofilm adherent to bovine enamel disks, coated with artificial saliva, was obtained. Biofilms were divided into four groups and were exposed to acoustic energy delivered by Sonicare for 0 (control group), 5, 15 and 30 seconds. The distance between the end of the bristles and the disk surface was set to 7 mm, to ensure that the biofilm removal was simply due to fluid forces and not to the contact with the bristle tips during the brushing cycle. A colorimetric technique (MTT assay), based on the reduction of a yellow tetrazolium salt to a purple formazan, was used to evaluate the reduction of the adherent biomass after the exposure to the sonic energy. RESULTS: ANOVA results showed that sonic energy exposure significantly reduced the biomass of S. mutans and S. salivarius adherent to the disks, while L. acidophilus and V. alcalescens seemed to remain basically unaffected. In the two streptococcal groups, the increase of the exposure time led to different reduction trends; while S. salivarius exhibited a progressive decrease over time, S. mutans showed a rapid reduction of the adherent biomass after a 15-second exposure to Sonicare.

Animals↗
PubMed2006

Clinical performance of posterior compomer restorations over 4 years.

PURPOSE: To clinically evaluate two polyacid-modified resin composites (Hytac and Dyract AP) for the restoration of posterior teeth over a 4-year period and to investigate accessible margins by light microscopy. METHODS: In a controlled prospective clinical study, 71 cavities (21 occlusal, 41 MO/OD, 9 MOD) in 30 patients were restored with compomers by three dentists. Thirty-eight restorations were placed with the combination OSB/Hytac, the same patients received 33 restorations with Prime&Bond 2.1/Dyract AP. Enamel margins of the cavities were etched with phosphoric acid. At baseline, after 12, 24, and 48 months, the restorations were examined by two independent investigators according to modified USPHS-criteria. Focusing on the 40 restorations available at all recalls, a semi-quantitative margin analysis was carried out at each recall using replicas and light microscopy at x130 magnification. RESULTS: Twenty restorations were not investigated at the 4-year recall (drop-out). After 48 months, 11 restorations (Hytac: n = 8, Dyract AP: n = 3) had to be replaced due to tooth fracture (n = 4), gap formation (n = 5), and adhesive failure (n = 2). Forty restorations were still in function after 4 years (overall failure rate 16%; Hytac: 21%; Dyract: 9%). Between the recalls, statistically significant differences were detected for the criteria marginal integrity (Alpha dropping from 76% at baseline to 32% after 4 years), restoration integrity (Alpha ratings at baseline 99% vs. 40% after 4 years), and occlusion (100% vs. 24%). For the criteria surface roughness (from the 6-month recall) and anatomical shape (after 4 years), a significant difference between the materials was evident in favor of Dyract AP. Except gap-free margins, the predominant criterion in the microscopic analysis at baseline was marginal overhang (24%) and 30% negative step formation after 4 years.

Acetone↗
PubMed2006

Dentin bridge formation after white mineral trioxide aggregate (white MTA) pulpotomies in primary molars.

PURPOSE: To evaluate, clinically and radiographically, the dentin bridge formation potential of white mineral trioxide aggregate (white MTA) when used in pulpotomy treatments in primary molars. METHODS: A total of 23 primary molars received a pulpotomy treatment using white MTA followed by stainless steel crown restoration and controlled 6 months after treatment. RESULTS: Clinical and radiographic success was 100% as none of the molars showed any clinical or radiographic pathological signs. Reparative dentin deposition was found in some of the cases: stenosis was present in 69.2% of the pulp canals from mandibular molars and formation of dentin bridges was seen in 11.5% of the pulp canals from mandibular molars 6 months after treatment with white MTA.

Aluminum Compounds↗
PubMed2006

The incidence of pulp healing defects with direct capping materials.

PURPOSE: To (1) study the injury and healing activity of the pulp tissue to calcium hydroxide [Ca(OH)2], resin composite (RC) and resin-modified glass-ionomer (RMGI) materials when used as direct pulp capping agents, and (2) compare the incidence of healing defects between these materials. METHODS: 135 Class V pulp exposed cavities were prepared in non-human primate teeth. Direct pulp capping was conducted over 6 to 730 days with hard set Ca(OH)2, RMGI and CR materials. Healing defects recorded were: (1) bacterial leakage with McKays stain; (2) operative debris including dentin fragments and particles of capping material; (3) pulpal inflammatory activity according to FDI standards; (4) area and absence of dentin bridge formation; and (5) presence of tunnel defects in bridge. Statistical analysis was evaluated using ANOVA. RESULTS: The capping materials were associated with varying levels of pulp healing defects, including tunnel defects (P= 0.0001); operative debris (P= 0.0001); pulpal inflammatory cell activity (P= 0.0073) and bacterial leakage (P= 0.0260). Other healing defects, and the area of dentin bridge were not influenced by capping materials (P> 0.05).

Analysis of Variance↗
PubMed2006

Clinical performance and SEM evaluation of direct composite restorations in primary molars.

PURPOSE: To evaluate the clinical outcome of composite restorations performed in primary molars after 18 months and the morphology of the dentin/resin interface. METHODS: 41 primary molars from children aged 4-9 years were restored with Scotchbond Multi-Purpose Plus adhesive system and Z100 resin-based composite. The restorations were evaluated at baseline, 6, 12 and 18 months using the USPHS method for direct clinical analysis. Plaster models were made at each evaluation period for indirect evaluation. For the morphologic analysis of the dentin/resin interface, seven exfoliated teeth were sectioned longitudinally in a mesio/distal direction and observed in the electro scanning electron microscope. RESULTS: 100% (n = 40) of the restorations evaluated at 6 months were scored as Alpha for anatomical form, color matching, secondary caries, color alteration, and marginal degradation. At 12 months, 96.4% (n = 28) of the restorations received Alpha score and 3.4% Charlie score. At 18 months, all restorations evaluated (27/27) received Alpha score. 23 restorations were indirectly evaluated at 6, 12 and 18 months postoperatively. No significant wear or fractures were observed in any of the restorations. In the evaluation of the dentin/resin interface, the formation of a consistent hybrid layer was observed and the restorations were well adapted to the dentin at 18 months postoperatively.

Acid Etching, Dental↗
PubMed2006

Clinical evaluation of self-etch adhesives in Class V non-carious lesions.

PURPOSE: To evaluate the clinical performance of two self-etching and one total-etch adhesives in Class V non-carious cervical lesions (NCCL). METHODS: Two self-etching primers, Clearfil SE Bond and Hybrid Bond, and one total etch adhesive, Admira Bond, were placed in 195 NCCL. Restorations were evaluated at baseline, 1 and 2 years using the USPHS criteria. RESULTS: No restoration was lost after 1 and 2 years for all materials. There was no significant difference between the baseline and 2-year results for Admira Bond and Clearfil SE Bond restorations. In contrast, Hybrid Bond restorations showed significant deterioration in marginal adaptation and cavosurface marginal discoloration after 2 years. Also, there was no significant difference between Admira Bond and Clearfil SE Bond at each recall period.

Acid Etching, Dental↗
PubMed2006

Clinical and microbiological effect of calcium hydroxide protection in indirect pulp capping in primary teeth.

PURPOSE: To evaluate clinically and microbiologically the effect of calcium hydroxide (CH) on carious dentin on primary teeth submitted to indirect pulp capping (IPC). METHODS: Twenty 4-7 year-old subjects with 42 treated teeth participated in the study. The treatment consisted of incomplete excavation of the demineralized dentin, application of a CH or gutta-percha (GP) layer and sealing with a resin-based composite for 4-7 months. After cavity preparation and sealing, the dentin was evaluated clinically (color and consistency) and microbiologically. Dentin samples were cultured on blood agar under aerobic and anaerobic conditions, in Mitis Salivarius agar and Rogosa SL agar. RESULTS: 39 teeth (20 in the CH Group and 19 in the GP Group) were reopened 4-7 months post-treatment for clinical and microbiological evaluation. In all teeth, the initial demineralized dentin was wet and soft or leathery. In the CH Group, 10% of the lesions were yellow, 80% light brown and 10% dark brown and in the GP Group, 94.7% were light brown and 5.3% dark brown. After treatment, the dentin was dry, 90% (Group CH) and 84.2% (Group GP) were dark brown. The final consistency was either leathery or hard. Three samples in the CH Group and five in Group GP changed from soft to leathery; only one sample (GP) remained leathery. 85% in the CH Group and 68.4% in GP Group turned hard after treatment. All bacterial counts decreased significantly by the end of treatment. In the CH Group, the bacterial (Log10 CFU + 1) anaerobic growth decreased from 4.84 +/- 1.31 to 1.35 +/- 1.54, aerobic from 4.09 +/- 1.04 to 0.92 +/- 1.30 and lactobacilli from 3.24 +/- 1.22 to 0.36 +/- 0.89, respectively; the mutans streptococci from 2.05 +/- 1.84 to 0.14 +/- 0.60. In GP Group, anaerobic growth decreased from 5.22 +/- 0.96 to 2.02 +/- 1.65 and aerobic from 4.23 +/- 1.37 to 1.08 +/- 1.29 and lactobacilli from 2.06 +/- 1.81 to 0.00 +/- 0.00, respectively; the mutans streptococci from 3.16 +/- 1.59 to 0.28 +/- 0.84.

Calcium Hydroxide↗
PubMed2005

Evaluation of resin composite materials. Part I: in vitro investigations.

PURPOSE: To evaluate different resin-based composites using a variety of in vitro investigation methods to predict their clinical behavior. METHODS: Materials selected for this study were Heliomolar radiopaque (microfilled), Tetric Ceram, Pertac II (minifilled hybrids), Ariston pHc (ion releasing hybrid), and Solitaire I (hybrid with porous fillers). The evaluated in vitro criteria were three-body wear according to the ACTA method, microtensile bond strengths to enamel and dentin, flexural strength (four-point bending strength), flexural fatigue behavior (flexural fatigue limit), and calcium ion release (for Ariston pHc). RESULTS: Concerning wear resistance, Ariston pHc (20.5 microm after 200,000 cycles) was inferior to the other materials (13.7-15.9 microm). Microtensile bond strengths to dentin were similar for Heliomolar (32.0 MPa), Tetric Ceram (30.4 MPa; both bonded with Syntac Classic), and Pertac II (30.8 MPa; bonded with EBS Multi) being above Solitaire I (22.5 MPa; bonded with Solidbond) being above Ariston pHc (13.2 MPa; bonded with Ariston Liner). Enamel bond strengths for Heliomolar (40.0 MPa), Tetric Ceram (36.5 MPa), and Pertac II (38.9 MPa) were significantly higher than for Solitaire I (26.6 MPa) which was above Ariston pHc (7.2 MPa). Heliomolar, Tetric Ceram, and Pertac II revealed higher micro-TBS to enamel than to dentin, Ariston showed the contrary, and Solitare exhibited no difference between enamel and dentin micro-TBS. Solitaire I exhibited a lower initial flexural strength than the other materials, the computed fatigue strength of the material even dropped to the level of glass ionomer cements (17.9 MPa). Long-term calcium release data for Ariston exhibited a continuously high calcium release becoming lower at the end of the observation beyond 21 months.

Acrylic Resins↗
PubMed2005

Scanning electron microscopic evaluation of fiber post-resin core units built up with different resin composites.

PURPOSE: To microscopically evaluate the structural characteristics of post-and-core units made of a fiber post and of different types of resin-based composites used as core materials. METHODS: 55 endodontically treated human maxillary incisors were prepared for receiving a fiber post (AEsthetic Post Plus). One-Step and C&B resin cement were used for luting the post. Samples were randomly divided into 11 groups. Eleven different composite materials were selected to build-up the abutment. The materials on trial were: Group 1: Z100; Group 2: Light-Core; Group 3: Lumiglass; Group 4: Gradia Direct; Group 5: Build-It!; Group 6: Tetric Ceram; Group 7: Biscore self-curing; Group 8: Unifil Flow; Group 9: Definite Flow; Group 10: Tetric Flow; Group 11: AEliteFlo. All the post-and-core specimens were cut perpendicularly to their long axis and processed for SEM observations. The presence of voids/bubbles within the resin abutment and of defects at the interface between the post surface and the core material was scored. These aspects were quantified with reference to a predefined index. The differences among the scores were tested for statistical significance (P< 0.05). RESULTS: Cores built up with flowable composites showed the highest integrity and the best adaptation onto the post.

Analysis of Variance↗
PubMed2005

Evaluation of resin composite materials. Part II: in vivo investigations.

PURPOSE: To clinically evaluate two different resin-based composites (Solitaire I and Ariston pHc) in order to determine the minimum clinical evaluation time needed to detect critical signs of failure. METHODS: In a controlled prospective clinical study, 99 cavities (30 Class I, 69 Class II) in 31 patients were restored (50 Ariston pHc without enamel etching and rubber dam, 49 Solitaire I restorations with total etching and rubber dam) and clinically investigated at baseline, after 6, 12, and 24 months. RESULTS: After 2 years of clinical service, 49 restorations (Ariston pHc: n = 38, Solitaire: n = 11) had to be replaced. The majority of failures occurred after more than 1.5 years. The reasons for replacement were differently distributed in both groups (Ariston pHc: 28 tooth fractures, 3 gap formations, 5 hypersensitivities, 1 bulk fracture, 1 marginal fracture. Solitaire: 5 gap formations, 1 hypersensitivity, 3 bulk fractures, 1 wear of the restorative material, 1 void in the restoration). Forty-four restorations were still in function after 2 years (overall failure rate after 2 years: 14%; Ariston pHc: 17%; Solitaire: 7%; survival analysis algorithm according to Kaplan/Meier). Comparing the materials, no statistical differences were evident except for the criteria "integrity tooth" (= tooth fracture or cracks) and "hypersensitivity" (from the 12-month recall; Mann-Whitney U-test; P< 0.05). In both cases of significant difference, Ariston pHc exhibited inferior results. After 2 years, only three teeth restored with Ariston pHc did not show considerably cracked enamel. The additional marginal analysis showed statistically significant differences for both materials regarding the criteria "perfect margin" (decrease), "gap formation" (increase), and "negative step formation" (increase; P< 0.05; Friedman 2-way ANOVA) between the four recalls. Therefore, a 2-year in vivo evaluation should be recommended prior to marketing a dental restorative material.

Acid Etching, Dental↗
PubMed2005

Effect of acidulated phosphate fluoride (APF) gel on the adherence of cariogenic bacteria to resin composites.

PURPOSE: To evaluate the effect of 1.23% acidulated phosphate fluoride (APF) and the subsequent polishing on the in vitro adherence of mutans streptococci to resin composites in a model that simulated the oral cavity conditions. METHODS: Samples of light-curing resin-based composites (Z100 and Z250) were treated with 1.23% APF gel (Sultan) for 1 minute and polished subsequently with Sof-Lex disks. The bacterial adherence of Streptococcus mutans and Streptococcus sobrinus to the APF gel treated resin samples and the subsequent polished samples were analyzed and compared with the adherence to the non-treated controls. RESULTS: The 1.23% APF gel caused a significant increase in the adherence of Streptococcus mutans and Streptococcus sobrinus. The increasing rate of the bacterial adherence to resin composites after APF treatment ranged from 73.5% to 167% and differed according to the bacterial strains. A decrease in the adherence of the bacteria was found after subsequent polishing with Sof-Lex disks.

Acidulated Phosphate Fluoride↗
PubMed2005

Conversion of one-step to two-step self-etch adhesives for improved efficacy and extended application.

PURPOSE: One-step self-etch adhesives have restricted use due to their acid-base incompatibility with autocured composites and their behavior as permeable membranes after polymerization. This study examined the feasibility of their conversion to two-step self-etch adhesives via the adjunctive use of a non-solvented, relatively hydrophobic resin coating. METHODS: iBond, Xeno III and Adper Prompt were used either in multiple coats, or in a single coat followed by the use of a layer of Scotchbond Multi-Purpose Plus bond resin for coupling to light- and auto-cured composites. Four types of experiments were performed. Bonded specimens were examined with TEM after immersion in an ammoniacal silver nitrate tracer. Fluid flow measurements of iBond were conducted using the two application protocols to compare the permeability of the bonded dentin with the original smear layer. Permeability of vital dentin bonded with both application protocols were compared for the transudation of dentin fluid across the bonded dentin. Microtensile bond strengths of dentin bonded with the two protocols were examined for their compatibility with an auto-cured composite. RESULTS: The results of the four experiments were complementary. iBond and Xeno III exhibited "apparent incompatibility" to auto-cured composites that resulted from their inherent permeability. This was confirmed by the presence of dentin fluid transudate on the adhesive surfaces when they were bonded to vital dentin. Conversely, Adper Prompt exhibited "true incompatibility" to auto-cured composites that was caused by adverse acid-base interaction, masking the inherent permeability of this adhesive. "True" and "apparent" incompatibility issues were eliminated upon their conversion to two-step self-etch adhesives.

Bisphenol A-Glycidyl Methacrylate↗
PubMed2005

Influence of different adhesive restorative materials on mutans streptococci colonization.

PURPOSE: To evaluate the effect of some restorative materials on mutans streptococci colonization. METHODS: Awild strain of mutans streptococci was isolated from human dental plaque and a monospecific biofilm adherent to the surfaces of 12 adhesive restorative materials (F2000, Dyract AP, Compoglass F, Z100 MP, Filtek Z250, Clearfil, Ketac-Bond, Ketac-Fil Plus, Ketac-Molar, Fuji Cap II, Fuji Bond LC and Fuji II LC) were tested. A colorimetric technique (MTT assay), based on the reduction of a yellow tetrazolium salt to a purple formazan, was used to evaluate the biomass adherent to the disk surfaces after a 24-hour growth. RESULTS: One-way ANOVA showed that glass-ionomer cements (Fuji Cap II, Ketac-Bond, Ketac-Fil and Ketac-Molar) had similar antibacterial effects on mutans streptococci and were significantly more effective (P < 0.001) than all other products tested in reducing the biofilm development on their surfaces. The compomers (Dyract, Compoglass F and F 2000) showed a significantly higher value of bacterial colonization than all the other materials (P < 0.001).

Adhesives↗
PubMed2005

Longevity of occlusally-stressed restorations in posterior primary teeth.

PURPOSE: To compile a survey of the longevity and reasons for failure of stainless steel crowns, amalgam, glass-ionomer, composite and compomer restorations in stress-bearing cavities of primary molars. METHODS: This work reviewed the dental literature of 1971 up to July 2003 for longitudinal, controlled clinical studies and retrospective cross-sectional studies. Only studies investigating the clinical performance of restorations in primary teeth with an observation period of at least 2 years were included. Annual failure rates of stainless steel crowns, amalgam, glass-ionomer, composite and compomer restorations were determined and failure reasons were discussed. RESULTS: Annual failure rates in stress-bearing cavities of primary molars were determined to be: 0-14% for stainless steel crowns, 0-35.3% for amalgam restorations, 0-25.8% for glass-ionomer restorations, 2-29.1% for atraumatic restorative treatments, 0-15% for composite restorations, and 0-11 for compomer restorations. Main reasons for failure were secondary caries, marginal deficiencies, fracture, and wear.

Compomers↗
PubMed2005

Application of biologically-oriented dentin bonding principles to the use of endodontic irrigants.

PURPOSE: To compare the removal of smear layer and the structure of the hybrid layer formed after the use of EDTA or MTAD solutions when used as a final flush. METHODS: Single-rooted extracted premolars (n=18) were collected and treated for root canal therapy using NaOCl irrigation followed by a final rinse of 17% EDTA, Biopure MTAD, or saline (negative control). The roots were obturated with gutta-percha and a hydrophilic HEMA-containing root canal sealer. The TEM specimens were impregnated with 50% silver nitrate to visualize sealing imperfections and nanoleakage. The structure of the coronal, middle and apical parts of root canal walls was examined using transmission electron microscopy. RESULTS: After NaOCl irrigation, a final rinse with BioPure MTAD or 17% EDTA completely removed the 2 microm-thick smear layer on mechanically instrumented root canal walls. The BioPure MTAD hybrid layer was thicker than the 17% EDTA hybrid layer. Both the BioPure MTAD and EDTA caused a collapse of the dentin matrix structure which impeded sealer infiltration and the formation of high quality hybrid layer bonding. The hybrid layers created in smear layer-covered dentin exhibited less potential for nanoleakage than the MTAD or EDTA hybrid layers.

Bicuspid↗