Dental research in Spain. A bibliometric analysis on subjects, authors and institutions (1993-2012).

BACKGROUND: Bibliometrics is defined as the use of statistical methods in the analysis of a body of literature to reveal the historical development of subject fields and patterns of authorship, publication, and use. Our objective was to characterize Spanish scientific output in Dentistry through the analysis of Web of Science database in a 20-year period. By means of a bibliometric study documents were statistically analyzed using indicators that showed quantitative and qualitative aspects of the production. Specifically, time course of the scientific production within the time span was analysed, as were the journals where the article was published and the categories of Journal Citation Reports (JCR) in which they belong, thematic areas, authorship, and finally authors and institutions with the highest production in Spain. MATERIAL AND METHODS: By means of the design of a specific search strategy previously described in the scientific literature, we recovered all citable documents about Dentistry signed by Spanish researchers and included in the WoS database between 1993 and 2012. RESULTS: A total of 3006 documents fulfilled the search criteria, of which 2449 (81.5%) were published in journals within the category Dentistry Oral Surgery and Medicine and 557 (18.5%) within other categories of the JCR. During the four quinquenniums studied, the production increased quantitatively (8.6-fold) and qualitatively. Finally, the universities of Granada and Complutense of Madrid were the institutions with the highest production and most prolific authors. CONCLUSIONS: The Spanish dental production sharply increased in the last two decades, reaching quantitative and qualitative levels similar to those of the other medical specialties in the country.

Trends in World Dental Research: an overview of the last three decades using the Web of Science.

OBJECTIVE: The objective of this paper is to analyse the scientific activity of dental sciences over the last 30 years. MATERIALS AND METHODS: Dental-research output was identified by retrieving all citable dental documents in the Web of Science (WoS) database in the periods 1986-1988, 1996-1998, and 2006-2008. For this, a two-phase search strategy was designed: firstly, output in Dentistry, Oral Surgery, and Medicine (DOSM) Journal Citation Reports (JCR) category journals were compiled; secondly, for journal documents of other JCR categories but related to Dentistry (Non-DOSM), an innovative search strategy was designed based on a double criterion, thematic and institutional. RESULTS: The results showed that DOSM production increased in absolute but decreased in relative terms over the last 30 years. The JCR categories where dental researchers publish also varied. Surprisingly, the geographic distribution of the production shows a growing concentration of the steadily fewer countries, a previously undescribed phenomenon, while the thematic analysis reveals that this production continued to form four broad thematic areas encompassing the remaining specialties: Dental Materials Prosthodontics, Orthodontics, and General Dentistry. CONCLUSIONS: Scientific production in dentistry has changed in the past three decades both quantitatively and qualitatively, as well as their geographical distribution despite being structured around the same specialties. CLINICAL RELEVANCE: In this study, along with some key messages about the key shifts in publication trends, in terms of subject, where published and by whom, we propose a new methodology which could be useful to professionals as well as researchers, in which the exhaustivity and precision rates for scientific information retrieval improve.

In vitro evaluation of the accuracy of three electronic apex locators.

The accuracy of three electronic apex locators (EALs) (Justy II, Root ZX, and Neosono Ultima EZ) is evaluated, together with the concordance of the measurements obtained by two different operators. Twenty single-root human teeth were used, sectioning the crown to gain access to the root canal. A first operator (A) determined the reference (or control) length (corresponding to the actual length) for each tooth, after which all teeth were measured individually and independently by the other two operators (B and C). The results obtained with each EAL and by each operator were in turn compared with the corresponding control length. The statistical analysis of the results showed EAL reliability in detecting the apex to vary from 80% to 85% and 85% to 90% (depending on the operator) for the Justy II and Neosono systems, respectively, whereas reliability was found to be 85% for the Root ZX device. These results, combined with a high interobserver concordance, suggest electronic root canal measurement to be an objective and acceptably reproducible technique.

Influence of different composite restoration techniques on cuspal deflection: an in vitro study.

Cuspal deflection produced by polymerization shrinkage was measured after using different composite restoration techniques. This study included 30 healthy premolars embedded in acrylic resin connected to a system that simulated intrapulpal pressure. A small ball was attached to each cuspal vertex as a reference point for intercuspal distance measurements. A large mesio-occlusal cavity was cut in each premolar. All premolars were treated with the same adhesive (ScotchBond) and composite (Tetric Ceram). The teeth were randomly distributed among three study groups: Group 1, filled with two horizontal increments; Group 2, filled with two horizontal increments, the first up to half the cavity height and light cured using a transparent plastic cone (Cerana), and the second filling the remainder of the cavity and Group 3, filled in the same way as Group 2, except that the first increment only filled one-third of the cavity height. The intercuspal distance was measured before beginning the restoration and immediately after polymerization of the first and second increments. Under the experimental conditions used, none of the filling techniques utilized avoided the cuspal deflection phenomenon. Polymerization of the final increment, which binds occlusal enamel in the buccal-lingual plane, was the main cause of cuspal deflection and produced a statistically significant reduction in intercuspal distance vs the baseline measurement in the three study groups. The global deflection ranged from 4 microm to 6 microm, depending on the filling technique used, although the differences among techniques did not reach statistical significance (p<0.05).

A comparative study of apical leakage of Endomethasone, Top Seal, and Roeko Seal sealer cements.

A comparison was made of the apical leakage of three sealers. Fifty single-root human teeth were randomly divided into 5 groups (n = 10; 3 experimental and 2 control). The teeth of the positive-control and experimental groups were instrumented with K-type files to size 45. The experimental groups were obturated by laterally-vertically, condensed gutta-percha with Endomethasone, Top Seal, or RSA sealer cements. The positive-control group was nonobturated and the negative-control group was noninstrumented. The root surfaces were then coated with nail varnish (except the apex in the experimental groups) and immersed in black ink (for 1 week at 37 degrees C). The statistical evaluation of the results obtained by clearing and cross-section techniques showed no significant differences between sealers. Leakage, as determined by the clearing technique, was significantly greater than that quantified by cross-section analysis.

Influence of time and thermocycling on marginal sealing of several dentin adhesive systems.

This study evaluated the in vitro microleakage of six dentin adhesive systems. Triangle-shaped Class V cavities with coronal margin in enamel and gingival margin in cementum or root dentin were cut in the buccal surfaces of 90 non-carious single-root human teeth. These teeth were randomly assigned into six groups (n = 15) for the evaluation of six different dentin adhesive systems: One Step, Prime & Bond 2.0, Syntac Single, Single Bond, Optibond Solo and Syntac Sprint. The preparations were restored with Degufill Ultra composite and polished using the Enhance system. Each group was randomly divided into three subgroups (n = 5): samples of the first subgroup were immersed in 2% methylene blue solution for seven days; those of the second subgroup remained in a similar solution for 31 days; those of the third subgroup were thermocycled 500x at 5-55 degrees C and immersed in 2% methylene blue for seven days. All 90 teeth were then embedded in methacrylate and bucco-lingually sectioned; the dye penetration was evaluated using an 0-4 ordinal scale. All of the dentin adhesive groups showed minimal leakage at the enamel margins with increased leakage at the gingival margins. Optibond Solo showed the best outcomes among the dentin adhesives tested.

The effect of various surface treatments and bonding agents on the repaired strength of heat-treated composites.

STATEMENT OF PROBLEM: Some clinical situations may require the repair of a secondary polymerized or aged composite. The higher indirect resin conversion rate may prove to be a disadvantage if a repair procedure based on covalent bonding from unreacted methacrylate groups is attempted. PURPOSE: This study evaluated the effectiveness of different combinations of surface treatments and 2 bonding agents used to enhance heat-polymerized and aged composite repairs. MATERIAL AND METHODS: Ninety Herculite XRV and 90 Heliomolar Radiopaque specimens were prepared and then postpolymerized and stored for 4 weeks. All composites were subjected to 1 of 9 treatment regimens that involved adding fresh composite onto a corresponding postpolymerized composite (Herculite/Herculite or Heliomolar/Heliomolar). The surfaces were treated with different combinations of air abrasion, phosphoric acid, hydrofluoric acid, acetone, Special Bond II, Heliobond, and Prime & Bond 2.0. RESULTS: Surface treatment with air abrasion resulted in the strongest repairs; surface treatment with phosphoric acid resulted in the weakest repairs. CONCLUSION: The use of air abrasion and Prime & Bond 2.0 adhesive consistently improved the shear bond strength for both composites tested.

Study of the shear bond strength of five one-component adhesives under simulated pulpal pressure.

Recently, several adhesive systems have been introduced that combine the primer and bonding resin in a single bottle. The purpose of this study was to evaluate the bonding efficiency of these one-component adhesives under conditions of simulated pulpal pressure and to determine the influence of storage time on the shear bond strength. One hundred caries-free human molars were embedded with epoxy resin in cylindrical rubber molds. Flat dentin surfaces at a level 1 mm above the pulpal chamber were obtained and used as the region for bonding. The specimens were randomly assigned to five groups (n = 20): (1) Syntac Single, (2) Prime & Bond 2.0, (3) One Step, (4) Single Bond, and (5) OptiBond Solo. Each bonding system was combined with the same composite resin (Herculite XRV). After resin polymerization, half of the samples from each group were tested at 1 week and the other half at 4 weeks. During the bonding procedure and storage time a pulpal pressure of 20 cm of serum was applied. Analysis of the data by one-way ANOVA testing showed that the shear bond strengths were significantly different (P < 0.001). OptiBond Solo and Single Bond presented the best results. As the storage time increased there was a significant decrease in the shear bond strength for all the adhesive systems used.