Presentations by UTU doctoral candidates

Clinical evaluation of dimethyl sulfoxide pretreatments on the durability of composite restorations

Omar A. Ismail, DDS, MSc

Background

“During the last decade, the understanding of mechanisms involved in the degradation of resin-dentin interfaces has substantially advanced” [1,2] and the traditional adhesive approaches have been considered as limited solutions to improve the durability of tooth-biomaterials interface. Replacement of old restorations may account for over 60% of all clinical restorative work, thus measures to improve resin-dentin bond durability have become one of the main research topics in adhesive dentistry [1,3–5]. There is irrefutable evidence showing that an ideal resin-enveloped collagen scaffold, created by current bonding protocols using relatively hydrophilic resins, is simply beyond expectations [4,6,7]. “A cascade of events invariably contributes to hybrid layer (HL) degradation resulting in failure of the adhesive interface” [3,5].

The adhesive group of Turku managed to make a breakthrough to solve the problem of hybrid layer (HL) degradation by introducing DMSO dimethyl sulfoxide as a new solvent that helps resin infiltration. A promising in vitro study had shown significant improvement of dentin bond strength up to 50 MPa instead of 30 MPa after pretreatment of dentin by DMSO. Nevertheless, there isn’t clinical study support this theory yet [8].

In this series of studies, an attempt will be made to test the performance of DMSO clinically. Such initiative should be covered by the approval of the ethical committee which had been granted from Cairo University in Egypt a highly ranked and respectful university. Many committees strictly revised the research plan and ensure that no harm will possibly affect any of the patients.

FDI criteria will be used to evaluate the biological, functional and aesthetic clinical performance of DMSO. The clinical studies will be done by me under supervision and collaboration between Cairo and Turku universities.

Two vitro studies will be done in the University of Turku related to the use of DMSO dentin pre-treatment prior to adhesive system, which can ultimately lead to the formation of new and improved guidelines that can dramatically enhance the quality and longevity of current adhesive systems and most importantly, in turn, improve the quality of treatment delivered to our patients.

Objectives

The aim of the following series of studies is to evaluate the feasibility of using DMSO clinically as new resin-dentin bonding protocols (i) by direct incorporation in commoner mixtures and (ii) as dentin pre-treatments to improve hybrid layer quality and to reduce the technique sensitivity of the etch-and-rinse bonding approach. This PhD thesis will be divided in four specific aims, corresponding to four independent studies. Each study will correspond to one publication to comply with the PhD title requirements.

Preliminary Results and Scientific Impact

More than half of the clinical work of general dentists is renewing old restorations due to the problems originated from bonded-interface failures. The economic burden of restoration replacements is high for the national health services. On the other hand, the biological cost is also very high for patients. The cycle of renewals may eventually lead to premature tooth loss, which would result in the loss of function. In this sense, the current adhesive strategies are still far from optimal. The expected results might provide clinically effective methods to increase the durability of restorations by the use of DMSO, which is essential to overcome both the biological cost and high renewal burden on the national health services.

We manage to restore 40 cases using the previously mentioned protocol in Study III and the preliminary results are very promising. I had to mention that we are the first group to use DMSO clinically. For further details, you could contact my supervisor professor Arzu Tezvergil head of the restorative department, Institute of Dentistry, University of Turku.

Salivary Macrophage Activation-Related Cytokines in Children with Type1 Diabetes Mellitus

Neslihan Yilmaz

Type 1 diabetes mellitus (T1DM) is related to the increased prevalence and severity of periodontitis and also impairs macrophage recruitment and differentiation. The aim of this cross-sectional study was to evaluate the salivary concentration of macrophage activation-related cytokines in children with and without T1DM in relation to periodontal status.

A total of 151 children (78 with T1DM and 73 systemically healthy) between 3-15 years-old were included in the study (Ethical permission number: E-71522473-050.01.04-15422). Unstimulated salivary samples were collected from all participants before dental and periodontal examinations. Salivary interferon gamma inducible protein-10 (IP-10), monocyte chemoattractant protein (MCP)-1, MCP-2, MCP-3, MCP-4, macrophage-derived chemokine (MDC), macrophage migration inhibitory factor (MIF), monokine induced by IFN-gamma (MIG) and, macrophage inflammatory protein-1 alpha (MIP-1α) concentrations were quantified using the Luminex® xMAP™ technique. All statistical analyses were run by a commercially available software (IBM SPSS Statistics for Windows, version 22.0, IBM Corp., Armonk, NY, USA)

Plaque index (PI%) and bleeding on probing (BOP%) were found significantly higher in individuals with T1DM while healthy group exhibited higher Decayed, Missing, Filled Teeth Index (DMFT) score. T1DM group demonstrated higher concentrations of salivary MCP-1 (p=0.003), MCP-3 (p<0.001), MIG (p=0.018) and, MIP-1α (p=0.016) compared to healthy individuals while the concentrations of MCP-2 (p=0.018) and, MCP-4 (p<0,001) were statistically higher in control group. After adjusting for age, PI%, BOP% and DMFT, significant differences in salivary MCP-1, MCP-2, MCP-4, and MIP-1α concentrations were observed between T1DM and control groups.

In conclusion, our results demonstrate that T1DM disrupts the salivary macrophage activation-related cytokine profile in children. These findings can be an outcome of the impaired systemic immune response in T1DM.

The list of presentations by UTU doctoral candidates is being updated.