Journal of Baghdad College of Dentistry

Objective: To conduct a standardized method for cavity preparation on the palatal
surface of rat maxillary molars and to introduce a standardized method for tooth correct alignment
within the specimen during the wax embedding procedure to better detect cavity position within the
examined slides. Materials and methods: Six male Wistar rats, aged 4-6 weeks, were used. The
maxillary molars of three animals were sectioned in the frontal plane to identify the thickness of hard
tissue on the palatal surface of the first molar which was (250-300µm). The end-cutting bur (with a
cutting head diameter of 0.2mm) was suitable for preparing a dentinal cavity (70-80µm) depth. Cavity
preparation was then performed using the same bur on the tooth surface in the other three animals.
Rats are then euthanized before dissecting, fixing, and demineralizing the teeth. For better alignment of
teeth samples during the waxing procedure, K-file endodontic instrument size #8 was dipped in Indian
ink. The file tip was inserted on the jaw bone at the buccal side of the tooth in a region opposed to the
prepared cavity on the palatal side. Moreover, a small Dycal applicator instrument was used to mark
the jaw bone on the mesial side of teeth samples as an orientation for the cutting surface. Results:
Well-defined sections were obtained with a clear cavity extension within dentin and without any signs
of pulp exposure in all samples. Conclusion: This pilot was conducted to perform an easy procedure
for cavity preparation in rat molar teeth to obtain a clear histopathological section.

Background: Color stability of glass ionomers (GIs) could be affected by many
factors such as pH and consumption of liquid medications like antibiotics. Most common
antibiotics used during childhood are amoxicillin suspension (AM.S) and azithromycin
suspension (AZ.S) which have acidic and basic pH respectively. Aim: to evaluate and
compare the effect of AM.S and AZ.S on color stability of nano resin-modified GI. Methods:
Thirty disc of nano resin-modified glass ionomer (2mm height x 4mm diameter) were divided
into three groups (n=10 for each) and independently exposed to AM.S, AZ.S, and artificial
saliva (A.S.). Color stability was evaluated in triplicate by VITA Easyshade® before and after
three immersion protocols, repeated over a three-week duration with two-days intervals. In
each protocol, samples were exposed for two minutes, three times daily for AM.S, once daily
for AZ.S, and A.S. full day. GI discs rinsed off after each immersion and kept in artificial saliva
until next immersion period. Results: One way ANOVA test and Post-hoc analysis of the
changes in color space compartments of nano-resin modified GI samples demonstrated just a
significant change (p˂0.05) in yellow-blue axis (Δb*) value after immersion in AM.S in
comparison with A.S. Total Color change values (ΔE) of nano resin-modified glass ionomer
samples also illustrated a significant effect (p˂0.05) between AM.S and A.S. only. The highest
(ΔE) value was recorded for samples immersed in AM.S (ΔE =12.5) followed by AZ.S (ΔE=6.5)
while the lowest was recorded for A.S. (ΔE=1.1). Conclusion: AM.S (the acidic medication)
exhibited a higher staining effect to nano-resin modified GI samples when compared with
AZ.S (the basic medication). Several factors such as low pH, more exposure time and coloring
material of the immersion media added critical roles in coloring instability.

Background: The microhardness of a composite resin is a vital parameter that
is used to determine its clinical behavior. Measuring the microhardness of a composite resin
has been used as an indirect method to assess its degree of conversion and extent of
polymerization. The purpose of this in vitro study was to evaluate the effect of three curing
distances (0, 2, and 4 mm) on the microhardness of the top and bottom surfaces of three types
of flowable bulk-fill composite resins (smart dentin replacement, Opus bulk fill flow, and
Tetric N). Material and method: Sixty-three specimens from the three types of composite
resins (n=21) were fabricated using Teflon mold with a 4mm depth and a 5 mm internal
diameter and cured for 20 seconds. For each material, three subgroups were fabricated
according to the position of the light curing tip from the top surface; at 0, 2, and 4 mm
distances. Microhardness was measured using the Vickers test with a 50-g load for 15 seconds
for the top and bottom surfaces of all the samples. Results: The microhardness values were
decreased in the following order; 0mm > 2mm > 4mm curing tip distance, for both sides and
Tetric N had the highest microhardness values. Significant differences in microhardness were
recorded between the top and bottom surfaces for all the specimens (p<0.05). Conclusion:
Increasing the distances between the tip of the light cure and the surface of flowable bulk-fill
resins can significantly decrease the microhardness of the bottom surfaces compared to the
top surfaces.

Background: The healing process involves the restoration of the body’s
structural integrity. The extracellular matrix, blood cells, cytokines, and growth factors are all
involved in this dynamic, intricate, multicellular process. Hemostasis, the inflammatory
phase, the proliferative phase, and the maturation phase are all included. Opuntia ficus-indica
oil (OFI) and Punica grantum (PGS) oil are extensively used natural treatments that are
regarded as advantageous for their sedative, spasmolytic, and anti-inflammatory properties,
as well as for angiogenesis promotion, fibroblast increase, collagen production and
deposition, and extracellular-matrix remodeling. Materials and methods: Twenty-four New
Zealand rabbits were used. Four circular wounds were induced on their dorsum skin with a
sterile biopsy punch (8 mm in diameter). A wound on the upper right side left with no
treatment healed spontaneously. A wound on the upper left side was treated with OFI. A
wound on the lower right side was treated with PGS oil. Finally, the lower left-side wound
was treated with a combination of OFI and PGS oils. After each healing period (days 3, 7, and
14), animals were sacrificed to collect specimens by cutting the skin at the edges of the wound
by about 5 mm. Results: Collagen formation was faster in the experimental groups than in the
control group. Conclusion: Among the experimental groups, the joint local application of OFI
and PGS oils was the most effective in improving wound healing by promoting the synthesis
of matrix collagen compared with controls.

Background: This study aimed to compare the surface microhardness (MH) and
mineral content of white spot lesions(WSLs) after using bioactive glass (BAG)casein phosphopeptides-amorphous calcium phosphate(CPP-ACP),and nanohydroxyapatite(Nano-HAP)
under pHcycling. Material and method:18 sound maxillary first premolar were used for the
study.10 were selected for the vickers microhardness test, For Energy-dispersive X-ray spectroscopy analysis (EDX), the remaining 8 premolar teeth were used, 40 sections of enamel
blocks (Four from each tooth) were produced from the middle part of the buccal and palatal
surfaces of teeth for MH test while 48 sections of enamel blocks (Six from each tooth) were
produced for EDX analysis. Enamel slabs were divided into four groups: control group that
preserved in DDW, Nano-HAP, CPP-ACP and BAG group, then were demineralised using
0.1 M lactic acid and 8 wt.% carboxymethylcellulose gel to create artificial WSL. The specimens were subjected to a pH cycling regime for 20 days. The remineralisation potential of the
specimens was studied by evaluating the surface MH, calcium (Ca), and phosphrous (P) at
different stages: baseline, after production of WSLs, and after treatment with different materials. The gathered data were statistically analyzed using repeated measures one-way
ANOVA test and the Bonferroni test. Results: The results showed that Nano-HAP had the
highest mean values of MH (157.699 kg/ mm2
), Ca (50.108), and P (24.840) followed by BAG
(MH=147.769 kg/ mm2
, Ca=47.408, P=22.285), and the lowest mean value was found in the
control group (MH=52.299 kg/ mm2
, Ca=35.291, P=17.228). Bonferroni’s and Tukey's HSD test
showed higher significant difference (p<0.05) from demineralization to remineralization
phase in all groups, except when compared control group with WSL (Demineralization)
showed non-significant difference (P>0.05). Conclusion:all tested agents have highly significant remineralizing potential. Nano-HAP has the highest potential for remineralizing initial
enamel caries lesions.

Background: Denture cleansing was an important step that could prevent the
spread of infection and improve a patient's health, the durability of the dentures, and the
overall quality of life; therefore, it was necessary to choose a suitable cleanser that, in addition
to being effective, did not have an unfavorable effect on the qualities of the denture base resin
itself when used for an extended period. For this purpose, this study aimed to evaluate the
effect of tea tree oil (TTO) on Candida albicans adhesion and the surface roughness property of
poly(methyl methacrylate) denture material after immersion in TTO. Methods: A total of 55
heat-cured acrylic resin specimens were used for C. albicans adherence and surface roughness
tests. They were distributed into groups (0.25%, 0.5%, 0.75%, and 1%) of TTO, distilled water
(DW), and 2% chlorhexidine digluconate, totaling five specimens for each group. The
specimens were immersed following their group for 10 minutes. Surface roughness was
determined by a profilometer, and C. albicans adherence was determined by measuring
optical density with a spectrophotometer. For comparisons between groups for surface
roughness and disinfection tests, one-way ANOVA was performed on the SPSS program,
considering α = 0.05. Results: TTO had a statistically significant effect on C. albicans adhesion
to heat-cured acrylic resin (P < 0.05) compared with negative control. Meanwhile, no
statistically significant difference was found between 0.75% and 1% TTO concentrations (P >
0.05), whereas the surface roughness test showed a statistically non-significant difference
between TTO concentrations and DW (P > 0.05). Conclusions: Immersion of acrylic resin in
TTO was effective in decreasing C. albicans adhesion to it, and the greatest decrease was
obtained by 1% TTO. The surface roughness test showed a non-significant difference in
acrylic roughness after immersion in TTO.

Background: This study aims to investigate the effect of fixed orthodontic
appliances and/or antihypertensive drugs on the weight of experimental rats. Materials and
Methods: Thirty-six male Wistar albino rats were subjected to a split-mouth design study, in
which an orthodontic appliance was inserted in one side to move the first molar mesially for
2 weeks while the other side acted as a control to tooth movement. The rats were allocated
into three groups: group A (n = 12), without any pharmacological treatment; group B (n = 12),
subcutaneous injection of bisoprolol fumarate (5 mg/kg) daily; and group C (n = 12), subcutaneous injection of valsartan (10 mg/kg) daily. A fixed orthodontic appliance with a closing
coil spring delivering 50 gm of force was used to move the first molar mesially while the
incisors served as an anchor unit. The weight of the rats was measured on days 1 (the day of
appliance insertion), 7, and 14. Results: No significant (P > 0.05) difference in the body
weight of rats was found among the three groups at each time point; however, significant (P
< 0.05) weight loss was noted after the first and second week of the experiment in all study
groups. Conclusion: The body weight loss of rats following the insertion of a fixed orthodontic appliance could be related to the effects of the appliance rather than the administered
antihypertensive drugs.

Background: Due to the complicated and time-consuming physiological
procedure of bone healing, certain graft materials have been frequently used to enhance the
reconstruction of the normal bone architecture. However, owing to the limitations of these
graft materials, some pharmaceutical alternatives are considered instead. Chitosan is a
biopolymer with many distinguishing characteristics that make it one of the best materials to
be used as a drug delivery system for simvastatin. Simvastatin is a cholesterol lowering drug,
and an influencer in bone formation process, because it stimulates osteoblasts differentiation,
bone morphogenic protein 2, and vascular endothelial growth factor. Objectives: histological,
histochemical and histomorphometrical analyses were carried out to evaluate the effect of
local application of chitosan simvastatin nanoparticles (ChSimN) on bone healing. Materials
and Methods: New Zealand rabbits (n=14) were used in this study. Two defects were made:
one on the right side (the experimental side) that received ChSimN and the other one on the
left side (the control side), which left to heal spontaneously. Seven rabbits were sacrificed after
2 weeks of the experiments, while the others after 4 weeks. Bone samples were taken for
histological and histomorphometric study after the sacrifice. Results: The histological study,
using both H&E and Masson’s Trichrome stain, revealed that the ChSimN group recorded an
increased amount of bone formation at both time points. Histomorphometrical analysis
recorded a significant increment in bone marrow and trabecular areas in the ChSimN group.
Conclusion: ChSimN had a pronounced effect on bone formation.