1.Shear Bond Strength and Failure Mode of Different Dental Adhesive Systems
Azizah Murtuzah Shekh ; Noor Azlin Yahya
Annals of Dentistry 2019;26(1):1-7
The study aimed to evaluate the shear bond strength (SBS) and to analyse the failure mode at the resindentine interface of different dental adhesive systems. A total of 75 sound premolar teeth were selected and
randomly assigned into five different adhesive groups (n=15): OptiBond Solo (OBS, total-etch), OptiBond Versa
(OBV, two-bottles, self-etch), Adhe SE Ivoclar (ADHE, two-bottles, self-etch), G-Bond (GB, one-bottle, selfetch), and OptiBond All in One (OBO, one-bottle, self-etch). The occlusal surface of each tooth was flattened
and composite resin cylinder (4x2 mm) was built up on the flat dentine surface using a custom made mould.
The specimens were then subjected to 500 thermal cycles between 5 °C and 55 °C and dwell time of 20s. The
SBS test was conducted using a universal testing machine at a crosshead speed of 0.5 mm/min. Data were
analyzed using one-way ANOVA and Dunnett T3 Test. Failure mode was determined as adhesive, cohesive or
mixed mode using a stereomicroscope and the data were analyzed using Fisher's exact test. The total-etch
(OBS) had significantly higher value of SBS than the two self-etch (ADHE and GB) adhesive systems. Within the
self-etch systems, OBV showed significantly higher SBS value compared to ADHE and GB. There were no
statistically significant differences between types of failure mode (p > 0.05) and adhesive group. It can be
concluded that the different compositions in the self-etch adhesive materials may contribute to the different
SBS value. The failure modes detected within all tested groups did not show clinically important differences
2.Effect of Dietary Challenges on the Flexural Properties of Resin-based Composites
Noor Azlin Yahya ; Lim Shi Yin ; Maria Angela Garcia Gonzalez
Annals of Dentistry 2021;28(1):52-60
This study aims to compare flexural strength and flexural modulus of different resin-based composites (RBCs) and to determine the impact of dietary solvents on flexural properties. Forty specimens (12x2x2mm) for each of two conventional (Aura Easy [AE]; Harmonize [HN]) and one bulk fill (Sonic Fill 2 [SF2]) were fabricated using customised plastic moulds. Specimens were light-cured, measured and randomly divided into four groups. The groups (n=10) were conditioned for 7 days at 37°C: in one of media: air (control), artificial saliva (SAGF), 0.02N citric acid and 50% ethanol–water solution. After conditioning, the specimens subjected to flexural testing. Two-way ANOVA and one-way ANOVA (post hoc: Tukey’s or Dunnett T3 tests) were used at =0.05. Significant differences in flexural properties were observed between materials and conditioning media. Flexural strength and modulus values ranged from 124.85MPa to 51.25MPa; and 6.76GPa to 4.03GPa, respectively. The highest flexural properties were obtained with conditioning in air. Exposure to aqueous solutions generally reduced flexural properties. In conclusion, the effect of dietary solvents on flexural properties were material and medium dependent. For functional longevity of restorations, patients’ alcohol intake should be considered during material selection. Dietary advice (reduce alcohol consumption) should be given to patients post operatively.
3.Intervention of White Spot Lesions. A Contemporary Review of 20 years
Phang Kun Mun ; Prema Sukumaran ; Noor Azlin Yahya ; Mohideen Salihu Farook
Annals of Dentistry 2022;29(2022):60-70
White spot lesion is incipient caries and it manifests as white opacity lesion on the demineralised enamel
surface. White spot lesions are a common adverse effect among post orthodontic patients. The prevalence of
white spot lesions in post orthodontic patients varies from 2% to 97%. Therefore, it is imperative for dental
practitioners to be able to manage white spot lesions. Thus, this article is a contemporary review on the
management of white spot lesions. After reviewing this article, it comes to a consensus that non- invasive
treatments should be the first line management of white spot lesions. Non-invasive treatments such as patient
education, motivation, oral hygiene reinforcement, and attempts to remineralise with various forms of fluoride
preparation should be prioritised in the treatment plan. If the white spot lesions fail to respond more invasive
treatment options might be considered.
4.Evaluation of internal adaptation of flowable and bulk-fill resin-based composites
Christina Maria Noel ; Nor Suhana Azni Satapa ; Noor Azlin Yahya ; Ros Anita Omar
Annals of Dentistry 2021;28(1):23-31
This study aimed to evaluate and compare the internal adaptation of bulk-fill resin-based composite restorative
materials with flowable composites as lining materials using self-etch adhesive system. Class I cavities
(2mmx4mm) were prepared on flattened occlusal surfaces of fifty extracted human premolars and randomly
assigned into five groups (n=10) according to the materials used: Beautifil Bulk-fill Restorative (BR); Beautifil
Bulk-fill Flowable (BF); Beautifil Flow Flowable F10 (BF10); and Self-etch adhesive (SEA). Group A: SEA+BR;
Group B: SEA+BF10+BR; Group C: SEA+BF+BR; Group D: SEA+BF10+SEA+BR and Group E: SEA+BF+SEA+BR. The
samples were thermocycled for 500 cycles, then sectioned mesiodistally, polished and pre-treated prior to
scanning electron microscopy (SEM) evaluation. From SEM images, measurement of adhesive and cohesive
adaptation failures was recorded at multiple sites of the pulpal floor and in between materials. Data were
analysed using one-way ANOVA and post-hoc Tukey tests (p<0.05). Cohesive failure in SEA was observed at the
pulpal floor with the lowest percentage in Group A (5.14%), and highest in Group C and E (>16%). However,
there were no significant difference among all groups. Adhesive failure was seen at the pulpal floor between
SEA+BF/BF10/BR and between SEA+dentine with the highest percentage of gaps formed in Group A between
SEA+dentine (6.62%) and SEA+BR (5.30%). Nonetheless, no significant differences were observed among all
groups with p=0.89 and p=0.70, respectively. With the use of BF/BF10 at the pulpal floor, adhesive failure was
reduced but resulted in increased of cohesive failure. However, both adaptation failures were absent between
materials (BF/BF10 and BR) regardless with or without application of SEA.
5.Surface Roughness of Tooth Coloured Restorative Materials
Mohd Shahminan Ibrahim ; Yap Kai Wen ; Maria Angela Garcia Gonzalez ; Noor Azlin Yahya
Annals of Dentistry 2020;27(1):41-49
This study compared the surface roughness of selected tooth coloured restorative materials that were polished according to manufacturers’ instructions and Sof-Lex. It also assessed the surface roughness of polished materials after thermocycling. Filtek Z350XT, Beautifil-Bulk Restorative and Cention N, were used in this study. A stainless steel mould (10mm diameter x 2mm height) was used to fabricate 75 cylindrical specimens: 15 Filtek Z350XT (FZ), 30 Beautifil-Bulk Restorative (BB) and 30 Cention N (CN). All 15 FZ specimens were polished with Sof-Lex. Fifteen BB and CN specimens were polished according to manufacturers’ instructions. The remaining fifteen BB and CN specimens were polished using Sof-Lex. All the specimens were subjected to thermocycling (1000 cycles). Surface roughness was assessed quantitatively with profilometry after specimen preparation (Mylar stage), polishing and thermocycling. Data were analysed using SPSS version 25.0 at α=0.05. When polished according to manufacturers’ instructions, BB had the lowest mean surface roughness (Ra) values (0.13±0.01μm) followed sequentially by CN (0.14±0.03μm) and FZ (0.15±0.02μm). The differences were not statistically significant. When polished with Sof-Lex, BB exhibited the smoothest surface (0.116±0.03μm) followed sequentially by and FZ (0.150±0.02μm) and CN (0.157±0.02μm). Thermocycling caused an increase in the Ra. The differences were statistically significant. All materials tested had Ra values below the threshold value of 0.2 µm at Mylar stage and after polishing with their recommended polishing system and Sof-Lex. Thermocycling produced rougher surfaces that did not exceed the threshold Ra value. Polishability was material dependent.
6.Effect of Resin Coating on Surface Roughness and Microhardness of High Viscous Glass Ionomer Cements
Jian Sheng Lee ; Wen Ni Chan ; Noor Azlin Yahya ; Ros Anita Omar
Archives of Orofacial Sciences 2021;16(2):209-221
ABSTRACT
High viscous glass ionomer cement (HVGIC) was recently developed for atraumatic restorative
treatment (ART). However, its moisture sensitivity remains a limitation thus protective coating
application is recommended. This study investigated the effect of resin coating on the surface roughness
and microhardness of two HVGICs (Riva Self Cure HVGIC [RV] and Equia® Forte Fil [EQ])
conditioned in food-simulating liquids (FSLs). Fifty standard disc-shaped samples were fabricated using
customised stainless-steel mould (10 × 2 mm). Coating was applied on top surface of all samples and
subsequently divided into five groups: air (control), distilled water, 0.02 N citric acid, heptane and 50%
ethanol-water solution. The samples were conditioned in FSLs at 37°C for seven days. Subsequently,
the surface roughness and microhardness of samples were measured using optical profilometry and
microhardness tester, respectively. SEM analysis was done for qualitative observation of surface
morphological changes. Data were analysed using one-way ANOVA, two-way ANOVA and posthoc Tukey’s test (α = 0.05). Interestingly, the results revealed that surface roughness was significantly
influenced by FSLs immersion, presence of coating and the materials itself (p < 0.001). The lowest
surface roughness was found on control coated samples: RV (50.98±4.25) nm and EQ (62.77±3.92)
nm, while the highest values seen on uncoated surfaces in citric acid: RV (505.26±31.10) nm and EQ
(350.33±15.36) nm. RV samples had the lowest microhardness of 54.97±2.48 Vickers hardness number
(VHN) post-immersion in citric acid. In conclusion, with the exception of RV conditioned in heptane
and ethanol, the uncoated HVGICs generally had higher surface roughness than the coated HVGICs.
HVGICs conditioned in citric acid showed the most significant increase in surface roughness and
reduction in microhardness.
Glass Ionomer Cements--adverse effects