BackgroundThe purpose of this study was to investigate variations in the root canal systems of permanent maxillary first premolars in a Yemeni population using a clearing technique.MethodsTwo hundred fifty permanent maxillary first premolar teeth extracted from Yemeni individuals were collected. A small hole in the center of the occlusal surface of each tooth was prepared and pulp tissue was removed by immersion in 5.25% sodium hypochlorite. Teeth were stored in 5–10% nitric acid solution for 5–6 days. Next, teeth were rinsed, dried, and dehydrated using ascending concentrations of ethanol (70, 95, and 100%) successively for 12 h each. Waterproof black ink was injected into the dried dehydrated teeth. Stained teeth were then rendered clear by immersion in methyl salicylate solution (98%) until evaluation. Root canal morphology of each tooth was then examined.Results54.8% of teeth were single-rooted, while 44.4% were double-rooted and only 0.8% had three separated roots. The most common canal system configuration was Vertucci type IV (55.6%). Eight specimens of the single-rooted premolars (3.2%) had new canal configurations that have not been recognized in previous published studies. Accessory canals and inter-canal communications were detected in a total of 52.8 and 34.4% of the specimens, respectively. The apical foramen was located centrally to the apex in 84.9% and apical deltas were found in 13.2% of the studied sample.ConclusionsYemeni permanent maxillary first premolars are mainly single-rooted and predominantly present Vertucci type IV canal morphology. The finding of additional canal configurations in this study is low but should be kept in mind when performing endodontic therapy for these teeth.

AimThe aim to this study is to evaluate the biocompatibility and antibiofilm actions of two nano-hydroxy apatite (NHA).MethodologyNano-hydroxy apatites are biomaterials use in direct contact with living tissues. Therefore, they should be tested for their safety beside assessment of their minimum inhibitory (MIC) and minimum bactericidal concentration (MBC) using broth microdilution method. One hundred and twenty extracted bovine incisors were collected and cleaned to ensure the absence of any defects. Enamel blocks with different size (2 × 2 × 3 mm) and (5 × 5 × 2 mm) were prepared from their labial surfaces using an isomet saw. Enamel blocks are used for detecting the suitable concentration will be used in the following experiments using energy dispersive X-ray analysis (EDX). The remaining enamel blocks divided into 5 equal groups to detect inhibitory effect against bacterial adhesion to the initial enamel caries like lesions using viable count technique beside the antibiofilm activity against mature biofilm of Streptococcus mutans (S. mutans) using confocal laser microscopy. The remaining enamel blocks were used as a representing data for detecting surface topography for each group by using the scanning electron microscopy (SEM).ResultThe data showed safety of NHA suspensions. Additionally, only NHA suspension of large nanoparticle size (NHA-LPS) had MIC of 1.25 mg/ml against S. mutans. Also, have the higher percentages of Ca and P in the enamel blocks. Furthermore, the lowest level of bacterial adhesion was recorded in (group III) treated by NHA-LPS which was non-significantly different with the positive control group V. Biofilm thickness in group IV treated with NHA-small particle size (SPS) recorded high biofilm thickness followed by group III. Interestingly, group III showed greater killing effect against mature biofilm which is slightly higher than the positive control group V. In group III, surface topography revealed very smooth enamel surface with closed pores. Accordingly, NHA-LPS suspension had antiadhesive, antibacterial, and antibiofilm effect against cariogenic S. mutans representing a promising possibility to be recommended for safe effective remineralization.

Aim: To evaluate the remineralization potential presented by surface metrology, of two remineralizing agents: CPP-ACPF (MI paste plus) and fluoride containing mouthwash (Aquafresh extra care mouthwash) on the induced acid erosion bovine enamel. Materials and Methods: Ten freshly extracted bovine permanent incisors were selected. The incisal one third of their crowns were sectioned by a slow speed diamond disc. The labial surface of each sample was examined under atomic force microscope (AFM) to record its surface roughness (Ra values). All samples were then demineralized by citric acid solution and reexamined under AFM .The demineralized samples were randomly divided into two equal groups I and II (5 samples each), according to the remineralization regimen used; samples in group I were treated with MI Paste plus while those in group II were treated with Aquafresh extra care mouthwash. All samples were reexamined under AFM to evaluate Ra values. Results: Acid erosion showed an increase of surface roughness value (72.85 nm) compared to that recorded for the original surface (38.45 nm). After remineralization, there was a decrease of the mean Ra value in group I (52.78nm) and group II (59.54 nm). ANOVA test revealed a statistical significant difference among base line data (original enamel surface), demineralized and remineralized samples in both groups. Scheffe`s test revealed a statistical significant difference between mean Ra value of demineralized samples versus that of base line data as well as that of remineralized samples in both groups. Conclusion: The tested CPP-ACP based compound offered a significant remineralization potential of initially eroded bovine enamel compared to the tested fluoride containing mouthwash as detected by reduced surface roughness.

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