BACKGROUND: The effectiveness of the application of topical fluorides in prevention of erosive tooth wear has been an issue of controversy in the literature. The objective of this systematic review was to assess in situ studies investigating the effects of using topical fluorides on prevention of erosive tooth wear MATERIAL AND METHODS: Two electronic databases PubMed/MEDLINE and Cochrane Central Register of Controlled Trials were searched. Eligibility criteria included in situ-controlled studies that assessed the effect of the erosive process without additional tooth brushing. The search involved English-written articles only. A total of 684 potentially relevant titles and abstracts were found after removal of duplicates, of which 22 full-text articles were selected. Seventeen studies were included in the qualitative synthesis of which 6 studies included in the meta-analysis. The following data were obtained for each study: authors, year of publication, country, study design, periods of study, duration, blinding, interventions (type/concentration/form), tooth substrate, location of the intraoral appliance, number of samples attached to each appliance, type of acidic media used for erosive challenge, duration of erosive challenge, subjects (number/age/sex), reported side effects -if any-, measuring device, amounts of tissue loss. RESULTS: The risk of bias of the included studies was assessed using the Cochrane Collaboration tool for assessing the risk of bias. A meta-analysis of the present study was performed using Comprehensive Meta-Analysis version 2.2.048 software. CONCLUSION: The use of oral hygiene products containing AmF/NaF/SnCl2 or NaF may be effective in the prevention of erosive tooth wear.

Recent advances in dental resin based restorative materials have given rise to development of composites for bulk placement, to replace the need for incremental layering. Clinical consequences of microleakage are secondary caries, pulp inflammation, marginal discoloration, postoperative sensitivity, and the longevity of filling. Surface hardness is one of the mechanical properties of the restoration that should always be taken into account, particularly when they are faced with large areas of heavy masticatory forces. Accordingly, the current study was conducted to investigate the effect of packing technique and curing time on the marginal sealing and surface hardness of two bulk fill resin composites. Standardized class II proximal box cavities were prepared on the mesial and distal surface of the selected premolar teeth with the total of 48 cavities. The prepared cavities were randomly divided into 2 main groups, 24 cavities each, according to the placement technique used for cavity restoration either placement of bulkfill single increment of 4 mm depth or incremental placement of two increments of 2 mm each. Each group was subdivided into 2 subgroups, 12 cavities each, according to the bulk fill composite resin used; X-trafil bulkfill composite and Quixfil bulkfill composite. These subgroups were then subdivided into two smaller groups, 6 cavities each, according to the curing times either curing for 10 seconds following the manufacturers' instructions or curing for 20 seconds. For all specimens, after bonding procedures, bulk-fill resin composites were manipulated and applied in cavities as the previously assigned methodology, specimens were then immersed in 2% methylene blue dye for 24 hours. Teeth were sectioned and viewed under a binocular stereomicroscope. Readings were recorded. A total of 80 cylindrical resin composite specimens were prepared. samples were divided into 4 groups according to the type of bulk fill composite (X-tra fil or Quixfil) and irradiation time (10s or 20s). The resin composite was applied in the mold, covered with mylar strips and light cured using LED light curing unit with an intensity of 1200mW/cm2. Vickers Microhardness tester was used with microindentation carried out using a load of 500g. Three readings for each surface were taken and an average reading was calculated.

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Recently, the etch-and-rinse and self-etching approaches are the two strategies of resin-based adhesive systems to accomplish the bonding to enamel and dentin. The increased amount of solvents and hydrophilic monomers in the adhesive formulations lead to greater amount of residual solvents entrapped in the adhesive layer. Consequently, the resulting polymers will be more susceptible to degradation over time. One of the methods for more durable bond includes the application of an additional layer of a hydrophobic resin coating over the polymerized simplified adhesive. The aim of this in-vitro study was to evaluate the influence of hydrophobic resin coating on micro-tensile bond strength of different adhesives Eighty freshly sound human molars were divided into three main groups according to method of bonding (A), where (A1) represents teeth bonded using Single Bond Universal Adhesive in total each approach, (A2) represents teeth bonded using Single Bond Universal Adhesive in self-etch approach while (A3) represents teeth bonded using Self Etch Future Single Bond DC Bonding System. Each (A) group will be then subdivided into two additional subgroups according to the addition of hydrophobic resin coating into (B1) which stands for teeth with additional hydrophobic resin coating and (B2) which stands for teeth without additional of hydrophobic resin coating. Each (AB) group will be finally subdivided into two smaller subgroups according to the effect of thermocycling, where (T1) denotes the teeth which were thermocycled, and (T2) denotes the teeth which were not thermocycled. The occlusal dentin surface of each molar was prepared on two levels: Superficial level (below the dentino enamel junction by 0.5 mm) and deep level (below the dentino enamel junction by 1.5 mm). For all specimens, after bonding procedures either total etch or self etch, a hydrophobic resin coating was added for the assigned groups. Resin composite was applied; thermo-cycling was done for the assigned groups. Teeth were sectioned into a series of 1 mm thick slabs and microtensile bond strength testing was done. Two representative specimens of each group were selected for Ultramorphological Examination. Mode of application, addition of adhesive layer and thermocycling had a significant effect on bond strength. Within the limits of this study, we concluded that regarding bonding efficacy to enamel and dentine, conventional 3-step etch-and-rinse adhesives are still not surpassed by the newer simplified self etch adhesive systems. Addition of the hydrophobic bonding resin coating improved bonding to dentine especially when used with all-in-one self-etch adhesive systems.