Cuspal Deflection and Adhesive Interface Integrity of Low Shrinking Posterior Composite Restorations

Kad je riječ o restaurativnim zahvatima u distalnom području trenuačno su u svim istraživanjima u središtu pozornosti nisko-kontrahirajući kompoziti. U vezi s tim obećavaju materijali dobiveni siloranskim kemijskim postupkom s prstenastim monomerima i kondenzabilni dimetakrilati s visokim postotkom punila. Materijali i metode: Na ekstrahiranim gornjim premolarima (n=10) promatran je otklon kvržica nakon svjetlosne polimerizacije transduserom s razlikovanjem direktne struje (DCDT-om) uz čuvanje adhezivne veze elektronskim mikroskopom (SEM-om) i dvama restorativnim sustavima. To su Filtek™ Silorane/Silorane System Adhesive (3M ESPE) i Premise™ Packable /OptiBond FL (KERR). Podaci su analizirani dvostranim t-testom. Rezultati: Vrijednost p< 0,05 postavljena je kao statistički značajna granica. Filtek™ Silorane može smanjiti otklon kvržica uzrokovan polimerizacijskom kontrakcijom, ali sumnja se može li se održati adhezivna veza. Zaključak: Premise™ Packable pokazao je veći otklon kvržica tijekom polimerizacije, ali i bolju adhezivnu vezu.Low shrinking resin composites are in the focus of research in posterior resin composite restoratives. In this context, the silorane-chemistry, incorporating ring-opening monomers and highly filled packable dimethacrylates seem to be most promising. Material and Methods: The goal of this study was to investigate cuspal deflection after light-curing in extracted upper premolars (n=10), using direct current differential transducers (DCDT), and adhesive interface integrity by scanning electron microscopy (SEM) evaluation, of two restorative systems: 1) Filtek™ Silorane/ Silorane System Adhesive (3M ESPE); 2) Premise™ Packable /OptiBond FL (KERR). Data were analysed using a two-tailed t-test. Results: A p-value < 0.05 was considered statistically significant. Filtek™ Silorane may reduce cuspal deflection associated to the polymerization process, but there is concern regarding durability of adhesive interface integrity. Conclusions: Premise™ Packable showed higher cuspal deflection and complete integrity of adhesive interface

Otklon kvržica i postojanost adhezivne veze kod restauracija s nisko-kontrahirajućim kompozitom u distalnom području Cuspal Deflection and Adhesive Interface Integrity of Low Shrinking Posterior Composite Restorations

Sažetak Kad je riječ o restaurativnim zahvatima u distalnom području trenuačno su u svim istraživanjima u središtu pozornosti nisko-kontrahirajući kompoziti. U vezi s tim obećavaju materijali dobiveni siloranskim kemijskim postupkom s prstenastim monomerima i kondenzabilni dimetakrilati s visokim postotkom punila. Materijali i metode: Na ekstrahiranim gornjim premolarima (n=10) promatran je otklon kvržica nakon svjetlosne polimerizacije transduserom s razlikovanjem direktne struje (DCDT-om) uz čuvanje adhezivne veze elektronskim mikroskopom (SEM-om) i dvama restorativnim sustavima. To su Filtek™ Silorane/Silorane System Adhesive (3M ESPE) i Premise™ Packable /OptiBond FL (KERR). Podaci su analizirani dvostranim t-testom. rezultati: Vrijednost p&lt; 0,05 postavljena je kao statistički značajna granica. Filtek™ Silorane može smanjiti otklon kvržica uzrokovan polimerizacijskom kontrakcijom, ali sumnja se može li se održati adhezivna veza. zaključak: Premise™ Packable pokazao je veći otklon kvržica tijekom polimerizacije, ali i bolju adhezivnu vezu. Ključne riječi kompozitne smole, polimeri; adhezivi, pretkutnjaci Većina smolastih kompozita (RBCs-a) koji se upotrebljavaju u reataurativnoj dentalnoj medicini imaju zajedničku osnovu -polimeriziraju slobodne radikale metakrilata. Taj postupak mijenja volumen materijala, što omogućuje napetost na spoju restauracija-zub poznatu pod nazivom &quot;polimerizacijski stres zbog kontrakcije&quot; (1). Takav stres nastaje u kompozitnoj masi te se prenosi na adhezivnu vezu (2) i zubnu površinu, što stvara otklon kvržica (3) te pukotine u okolnoj caklini i dentinu (4). Sve to pacijent doživljava kao postoperativnu preosjetljivost (5). Polimerizacijski stres može kompromitirati vezu zuba i restauracije te završiti bakterijskim mikrocurenjem (6) i na kraju rubnim obojenjem, sekundarnim karijesom, upalom zubne pulpe i nekrozom (7)

Influence of Air-Barrier and Curing Light Distance on Conversion and Micro-Hardness of Dental Polymeric Materials

This study aims to assess the conversion degree and hardness behavior of two new commercial dental restorative composites that have been submitted to light curing in different environments (air and glycerin, respectively) at various distances from the light source (1 to 5 mm) and to better understand the influence of the preparation conditions of the restorative materials. Through FT-IR spectrometry, the crosslinking degree of the commercial restorative materials have been investigated and different conversion values were obtained (from ~17% to ~90%) but more importantly, it was shown that the polymerization environment exhibits a significant influence on the crosslinking degree of the resin-based composites especially for obtaining degrees of higher polymerization. Additionally, the mechanical properties of the restorative materials were studied using the nanoindentation technique showing that the nano-hardness behavior is strongly influenced not only by the polymerization lamp position, but also by the chemical structure of the materials and polymerization conditions. Thus, the nanoindentation results showed that the highest nano-hardness values (~0.86 GPa) were obtained in the case of the flowable C3 composite that contains BisEMA and UDMA as a polymerizable organic matrix when crosslinked at 1 mm distance from the curing lamp using glycerin as an oxygen-inhibitor layer

Validity and Reliability of the Dental Neglect Scale among Romanian Adults

The Dental Neglect Scale (DNS) is a well-known measure for assessing behaviours and attitudes related to oral health. However, the factor inconsistency revealed by the literature involves further investigations. The study focuses on the validation of the DNS in the case of a sample of the adult population from Romania. In this regard, data were collected online from 872 adults (616 females and 256 males). DNS reliability was examined from the perspective of internal consistency. Convergent validity was performed by associating DNS with different scales from the oral health field. In order to examine and confirm the factorial structure, the sample was broken down into two subsamples which made the subject of the exploratory factorial analysis (EFA) and confirmatory factorial analysis (CFA), respectively. DNS-RO is positively associated with the scale which measures the values related to oral health (OHVS) and negatively with those that assess the impact of the oral health on life quality (OHIP-14), the distrust of the benefits of oral health services (R-DBS), and reduced need for oral care (DIS). The Cronbach&rsquo;s &alpha; = 0.70, McDonald&rsquo;s &omega; = 0.70 and CR = 0.77 are acceptable. Both EFA and CFA (&chi;2/df = 1.13; CFI = 0.99; RMSEA = 0.017; SRMR = 0.059) support the unifactorial structure of the scale. The gender differences show that females evince greater care for oral health than male subjects. The study shows that the DNS-RO can be used to assess the behaviours and attitudes towards oral health in the case of the Romanian adult population in epidemiological studies and health promotion programs through health education

Oral Habits during the Lockdown from the SARS-CoV-2 Pandemic in the Romanian Population

Background and Objectives: The SARS-CoV-2 pandemic led to changes in population daily patterns. In order to adapt oral health promotion measures for future similar conditions, the main objective of the study was to assess changes in dental hygiene and eating and smoking habits during the government lockdown in Romania. Materials and Methods: The cross-sectional study was conducted immediately after the end of the lockdown and consisted of 800 adult subjects. Data collection was done via an online survey. Participants were divided into two groups: non-medical/dental practitioners (N-M/D group) and medical/dental practitioners (M/D group). Results: An increased use of dental floss from 27% (pre-lockdown) to 30.5% (during lockdown) was identified in the M/D group, while the manual toothbrush usage increased to 64.8% (during lockdown) from 61.7% (pre-lockdown) in the N-MD/group. No significant differences regarding toothbrushing frequency were observed in either group. A change in the number of daily snacks was identified in both groups (3&ndash;4 snacks per day: from 11% to 20.2% in the N-M/D group, from 13.1% to 22.2% in the M/D group). The consumption of sweets as a preferred snack was also noticed. A decrease of tobacco consumers was assessed in the lockdown period (from 66.6% to 60.4% in the M/D group, from 68.5% to 61.9% in the N-/M/D group). Conclusions: Oral habits were changed during the pandemic lockdown through the increase in the frequency of the consumption of snacks and sweets and the decrease in frequency of smokers. Only minor changes were observed in oral hygiene

Raman Spectroscopy as Spectral Tool for Assessing the Degree of Conversion after Curing of Two Resin-Based Materials Used in Restorative Dentistry

(1) Background: The treatment of dental cavities and restoration of tooth shape requires specialized materials with specific clinical properties, including being easy to model, light-cured, having a natural color, reduced shrinkage, a hardness similar to hydroxyapatite, and no leakage. The dimensional stability of resin composite materials is affected by polymerization shrinkage, degree of conversion (number of π carbon bonds converted into σ ones), thermal contraction and expansion, and interactions with an aqueous environment. (2) Methods: The materials used in our investigation were two composite resins with similar polymer matrices, but different filler (micro/nano filler). To evaluate the properties of samples, we employed the pycnometer technique (pycnometer from Paul Marienfeld Gmbh, Lauda-Königshofen, Germany), RAMAN spectroscopy technique (MiniRam Equipment from B&W Tek Inc., Plainsboro Township, NJ, USA; 785 nm laser source), SEM and EDX (FEI Inspect S.). (3) Results: The size of the filler plays an important role in the polymerization: for the pycnometric results, the larger particle filler (Sample 1) seems to undergo a rapid polymerization during the 45 s curing, while the nanoparticle filer (Sample 2) needs additional curing time to fully polymerize. This is related to a much larger porosity, as proved by SEM images. The lower degree of conversion, as obtained by Raman spectroscopy, in the same geometry means that the same volume is probed for both samples, but Sample 1 is more porous, which means less amount of polymer is probed for Sample 1. (4) Conclusions: For the two composites, we obtained a degree of conversion of 59% for Sample 1 and 93% for Sample 2, after 45 s of curing

Performance Assessment of Three Similar Dental Restorative Composite Materials via Raman Spectroscopy Supported by Complementary Methods Such as Hardness and Density Measurements

(1) Background: A widespread problem in oral health is cavities produced by cariogenic bacteria that consume fermentable carbohydrates and lower pH to 5.5–6.5, thus extracting Ca2+ and phosphate ions (PO43−) from teeth. Dental restorative materials based on polymers are used to fill the gaps in damaged teeth, but their properties are different from those of dental enamel. Therefore, a question is raised about the similarity between dental composites and natural teeth in terms of density and hardness. (2) Methods: We have used Raman spectroscopy and density and microhardness measurements to compare physical characteristics of several restorative dental composites at different polymerization intervals. (3) Results: XRVHerculite®, Optishade®, and VertiseFlow® showed the very different characteristics of the physical properties following four polymerization intervals. Of the three composites, OptiShade showed the highest polymerization rate. (4) Conclusions: Only fully polymerized composites can be used in teeth restoring, because incomplete polymerization would result in cracks, pitting, and lead finally to failure