Chiang Mai Dental Journal

A Study of Flexural Properties of Poly Methyl Methacrylate Reinforced with Various Amount of Silanized nano Alumina

Rittha Maphakdeewong — 2021-10-12

Abstract

Purposes

To study the concentration of silane coupling agent that forms monolayer on nano-alumina particles and the effect of silanized nano-alumina particles mixed in acrylic resin on flexural strength and modulus of elasticity.

Materials and Methods

Concentrations of silane coupling agent were calculated and analyzed by organic element analysis. The concentration was used for silanization of nano-alumina particles and silanized nano-alumina particles were mixed with acrylic resin at 0.25, 0.5, 0.75, 1, 3 and 5% w/w, producing the experimental groups. The control group was acrylic resin without nano-alumina. The specimens were 10 mm in width, 64 mm in length and 3.3 mm in thickness. Flexural strength and modulus of elasticity were investigated for all groups and were analyzed using one-way ANOVA at 95% confidence intervals.

Results

The concentration of silane coupling agent that forms monolayer on nano-alumina particles was 0.118 g for nano-alumina particles 1 g. The average flexural strength ranged between 75.86-100.63 MPa. The average modulus of elasticity ranged between 3.06-3.92 GPa.

Conclusion

The highest average flexural strength was found in the 0.25% w/w silanized nano-alumina group (100.63±14.05 MPa) and was significantly different from control group. The average modulus of elasticity values was found in the 0.5% w/w silanized nano-alumina group (3.92±0.81 GPa) and was significantly different from control group.

Keywords: flexural strength, methyl methacrylate, modulus of elasticity, nano-alumina particles, silane coupling agents

Oral cancer patients’ perspectives to quality of life: a qualitative study in the context of Northern Thailand medical and cultural systems

Thatsanee Saladyanant — 2021-10-12

Abstract

Objective: To investigate oral cancer patients’ perspective on quality of life; to explore how do medical systems works in the context of cultural systems in Northern Thailand.

Materials and Methods: A phenomenological study was conducted to make an understanding on oral cancer patients experiences and their perceptions on quality of life. Twelve oral cancer patients were recruited for in-depth, semi-structured interviews. The diverse experiences from patients who have been diagnosed with oral cancer from 2 months to 11 years were collected and the narratives were extracted, categorized, and analyzed into significance themes by using content analysis.

Results: Four themes emerged from the interviews including: (1) ability to cope with cancer under the supportive cultural healing, (2) family support and social network, (3) accessibility and availability of medical care, and (4) acceptance of new identity. Patients’ health believes and values were attached firmly to cultural explanation of disease and expressed through health seeking behaviors. Biomedicine together with cultural medicine both played their roles for oral cancer healing. Culture defined meaning of oral cancer and identify healing, thus, patients used pluralistic medicine to cure diseases and heal their illness.

Conclusions: The stigma of cancer is the unprepared-suffering death causes by uncleared factors. Patients believed Karma and curses were causes of cancer. Oral cancer patients need both biomedicine and cultural medicine to heal their organs, emotion, mind, and soul. Supports from social network, government health policy, and socio-cultural constructs help patients to perceive a good quality of life.

Effectiveness of Maprang “Bouea macrophylla Griffith” seed extract against endodontopathogenic microorganisms in a multispecies bacterial-fungal biofilm.

Warat Leelapornpisid — 2021-10-12

Objective:This study aimed to assess the antimicrobial efficacy of seed extractderived from Bouea macrophyllaGriffith (Maprang wan)grown in Northern Thailand against Entercoccus faecalis,Streptococcus gordoniiandCandida albicans inplanktonic and multispecies biofilm.

Materials and methods:Agar diffusion and broth microdilution methods were performed to investigate the antimicrobial activities of ethyl acetate extract of Maprang wan seed against planktonic E. faecalis,S. gordoniiand C. albicans.Growth curves of E. faecalis,S. gordoniiand C. albicansin 1:1:1and1:1:0.1ratio, respectively) were performed to measure the appropriate ratio of the species within biofilm. Multispecies of E. faecalis,S. gordoniiand C. albicansbiofilms were grown in RPMI for 48 hours at 37°C. Following this, the biofilms were exposed to 25 mg/mL of Maprang seed extracts. 0.02 mg/mL chlorhexidine was used as the positive control and RPMI as the negative control. After exposure, time-kill assay was conducted to evaluate time-point of the extract which showed bactericidal and fungicidal effects. The colony forming unit (CFU) data were analysed with one-way ANOVAand Dunnett's test (p<0.05).

Results:Maprang seed extract demonstrated the antimicrobial activity against planktonic and multispecies E. faecalis,S. gordoniiand C. albicans. The time kill assay showed a time dependent action of Maprang seed extract, itdemonstrated significant reduction of viable organisms at the time periods.

Conclusions:Maprang seed extract had antibiofilm property against multispecies E. faecalis,S. gordoniiand C. albicansbiofilms. The antimicrobial activity of the extract was comparable to chlorhexidine. Maprang seed extract has potential as a novel antimicrobial agent and could be used to treat superficial infections or as aroot canal medicament.

Antibiofilm Effect of Citric Acid-modified Chlorhexidine Gluconate on a Dual-species Biofilm

Warat Leelapornpisid — 2021-10-12

Objective: The purpose of this study was to compare the antibiofilm effect of chlorhexidine gluconate (CHX) added with citric acid (CA) on bacterial-fungal biofilm.

Methods: Dentin slices were sectioned from the crown of extracted human third molars. After sterilization, samples were inoculated with Enterococcus faecalis(E. faecalis) and Candida albicans(C. albicans) for 14 days to establish a bacterial-fungal biofilm. All samples were randomly divided into four treatment groups: phosphate-buffered saline (PBS) (negative control), 2% CHX, 10% CA, and 10% citric acid-modified 2% chlorhexidine gluconate (CAmCHX). Each dentin slice was treated with one of the solutions for 1 min. Following treatment, samples were labeled with a fluorescent viability stain to identify live and dead cells. The proportion of dead cells to total cells was analyzed with confocal laser scanning microscopy (CLSM), and biofilm removal efficacy was evaluated with scanning electron microscopy (SEM).

Results:10% CA and CAmCHX groups demonstrated a higher proportion of dead cells to total cells than the PBS group (P<0.05). No significant difference was observed between the 10% CA and CAmCHX groups (P>0.05). SEM images revealed less remaining biofilm in 10% CA and CAmCHX groups. Whereas, in 2% CHX and PBS groups, the biofilmstructure was intact.

Conclusions: Within the limitations of this study, CAmCHX demonstrated an antibiofilm effectagainst E. faecalisand C. albicansbiofilm on the surface of dentin slices.

Keywords: Chlorhexidine, Citric acid, Enterococcus faecalis, Candida albicans,Biofilms

The effect of surface treatments application on dentin permeability and shear bond strength of resin cement under simulated pulpal pressure condition

Napatsorn Dusadeedumkoeng — 2021-10-12

The objective was to evaluate the permeability reduction and bond strength after treated dentin with two surface treatment agents, Teethmate^® (TDA) and Portland cement.

Sixty extracted teeth were divided equally into six groups; control, TDA and Portland cement groups with and without simulated 15 cmH₂O pulpal pressure. Each surface treatment was randomly applied to dentin surface. Dentin permeability was evaluated for simulated pulpal pressure groups by recorded fluid droplets on dentin surface using replica technique. The replica was examined under SEM. The specimen was re-polished and re-applied same surface treatment. The composite rod was bonded to dentin with self-etched resin cement. The shear bond strength of bonding interface was tested with universal testing machine. Two-way ANOVA was tested for comparing treatment groups and pulpal pressure conditions with Tukey’s multiple comparisons.

Specimens with simulated pulpal pressure had significantly lower shear bond strength than without pulpal pressure (P<0.01). Surface treatment groups, TDA and Portland cement, showed significantly higher shear bond strength than control under simulated pulpal pressure condition (P<0.05). While no significant difference was seen in non-simulated pulpal pressure groups. SEM micrograph shown that both surface treatment groups had significant less permeability of dentin as smaller fluid droplets were recorded.

Dentin surface treatments had effectiveness on reduced dentin permeability and increased shear bond strength of dental adhesive in simulated pulpal pressure condition. But there had no advantage over a control group for non-simulated pulpal pressure condition.

Study of Flexural Properties between Domestic Glass Fibers Reinforced Polymethylmethacrylate and Dental Glass Fibers Reinforced Polymethylmethacrylate

Pattarika Angkasith — 2021-10-12

The aim of this study was to examine the flexural properties of PMMA reinforced with domestic glass fibers compared to PMMA reinforced with dental glass fibers. Thirty-two PMMA bar specimens in the size of 10x64x3.2 mm³(ISO 20795-1) were divided equally into 4 groups (eight specimens for each) according to the types of fibers: 1) no fibers 2) dental fibers 3) silane impregnated domestic glass fibers 4) non-silane impregnated domestic glass fibers. All specimens were subjected to 2,000 cycles of thermocycling. Flexural strength was determined using a three-point loading test set up at a crosshead speed of 5 mm/min by Universal Testing Machine Model 5566. Scanning electron microscopy was used to examine the microstructure of the cracked surface at 200X and 1000X. The results were analyzed by One-way ANOVA and Tukey HSD (α=0.05). Results: The silane impregnated domestic glass fibers demonstrated the highest flexural strength compared to the others while the non-impregnated domestic glass fibers had the lowest flexural strength. CONCLUSION Reinforcing PMMA with silane impregnated domestic glass fibers could improve its flexural strength. Keywords: Flexural Properties, Glass Fibers, Polymethylmethacrylate, Silane Coupling Agent

The Effect of Liquid Toothpaste compared with Conventional Toothpaste on Plaque Score

Prim Auychai — 2021-10-12

Abstract

Introduction: The new product, a liquid toothpaste, has been introduced to the market. It is claimed that its liquid form can better clean the proximal surfaces of the tooth, improves gingival health and controls bacterial growth.

Objective: To investigate the effectiveness of a liquid and a cream toothpaste on dental plaque score.

Materials and Methods: Thirteen subjects, aged 20–23 years old participated in this randomized controlled crossover clinical study. The study was conducted in 2 phases of 4-weeks each with a washout period of 1 week between phases. The subjects were randomized into two groups: Jintan-NUDE aqua mint^® and Colgate Total Advance Fresh^® and instructed to perform routine brushing with the assigned toothpastes. Total plaque scores (PS) and proximal plaque scores (PPS) were assessed by one examiner using a Turesky modification of the Quigley and Hein plaque index (TMQHI) 4 times during each phase: baseline (t₀), immediately after use (t₁), after the second week (t₂), and fourth week (t₃) of toothpaste use. Repeated ANOVA was used to compare the differences within each group and the independent t-test was used to compare the differences between groups at t₀, t₁, t₂, and t₃ at p<0.05.

Results: The mean PS and PPS of the groups were not significantly different at each evaluation point, except for the PS of the liquid group at t₂, which was significantly higher than that of the cream group. The PS and PPS in each group at t₁ were significantly lower compared with t₀, t₂, t₃ and the PS of the liquid toothpaste group at t₂ was significantly higher than that at t₀. The differences between the other time points were not significant.

Conclusion: Overall, the liquid and cream toothpastes have similar effectiveness in controlling plaque scores at the proximal surfaces of the teeth and total plaque scores. This study indicates that liquid toothpaste is an alternative to cream toothpaste

Effects of Mechanics for Uprighting Partially-Impacted Mandibular Second Molars using Miniscrew Anchorage: A Finite Element Analysis

Puttnaree Kittichaithanakoon — 2021-10-12

Objectives: The purposes of this study were: (1) to evaluate the optimal force magnitude that can be applied to the initial uprighting of partially-impacted mandibular second molar (tooth 37) without exceeding the hydrostatic pressure of the periodontal ligament (PDL) capillary vessels’ blood pressure, which is 0.0047 megapascal (MPa)
and distribution pattern of hydrostatic pressure on PDL 37; and (2) to describe initial tooth displacement of the impacted tooth 37, mandibular first molar (tooth 36) and mandibular second premolar (tooth 35) using the finite element method.
Materials and methods: A three-dimensional (3D) finite element model was developed from CBCT images. Various pushing forces, 35 to 150 g were applied to evaluate the optimal force magnitude. A force direction was laid from an interradicular miniscrew head, which was placed in the cortical bone between the root 35 and root 36, to a buccal minitube on the impacted tooth 37. The optimal force magnitude was used to simulate the initial tooth displacement of impacted tooth 37, tooth 36, and tooth 35.
Results: The optimal force magnitude, when a single-pushing-uprighting force applied, was 80 g. The compressive hydrostatic pressure on PDL 37 appeared on the disto-lingual region close to the cemento-enamel junction (CEJ); and the tension on PDL 37 appeared on the mesio-buccal side of the mesial root and on the mesio-buccal side of the distal root close to the furcation. The initial displacement pattern of the impacted tooth 37 was lingual crown tipping, distal crown tipping, distal root tipping, and disto-lingual rotation of the crown. It was found that the teeth 36 and 35 were also displaced, though force was not directly applied to them. Teeth 36 and 35 showed lingual crown tipping, extrusion, and distal crown tipping.
Conclusions: This finite element analysis was revealed that the force magnitude that can be applied to initial uprighting the mandibular second molar for this study was 80 g. The initial displacement pattern of the mandibular second molar, as descending order, was lingual crown tipping, distal crown tipping, distal root tipping and disto-lingual rotation of the crown. It was also revealed that the adjacent teeth were displaced, even though uprighting force was not directly applied to them.

Biologic effects of pulp capping material containing fluocinolone acetonide on human dental pulp cells

Phumisak Louwakul — 2021-10-12

The aims of this study were to test some biological properties of pulp capping material containing fluocinolone acetonide (PCFA). The PCFA is hard setting calcium hydroxide cement containing 50 mmol/L of fluocinolone acetonide (FA). Cytotoxicity and cell proliferation were evaluated by MTT assay. RT-PCR and Western blotting were used to study the effects of PCFA on RNA (dentin sialophosphoprotein: DSPP) and protein (dentin sialoprotein: DSP) synthesis. Anti-inflammatory effect of PCFA was determined by analysis of cyclooxygenase 2 (COX-2) expression. Dycal^® was used as control. The results suggested that the diluted conditioned media from PCFA slightly increased cell proliferation, significantly increased DSPP expression and decreased COX-2 expression (p < .05). In term of biologic properties, the PCFA may promote cell proliferation, mineralization and decrease pre-existing inflammation in human dental pulp cells. It may be considered as an alternative pulp capping material in the treatment of inflamed dental pulp.

Vertical Root Fracture Findings From Cone Beam Computerized Tomography (CBCT): A Serial Case Analysis

Weerapan Aunmeungtong — 2021-10-12

The diagnosis of vertical root fracture (VRF) has been discussed as a difficult and complicate issue to make the definitive diagnosis. With the using of a new modality image diagnosis, cone-beam computed tomography (CBCT), it may help to identify the VRF.The purpose of the study was to describe the CBCT findings of the VRF and relevant clinical findings.Nine patients with tentative diagnosis of VRF were included in the report. All patients were sent for CBCT. Most of the CBCT clearly showed peri-radicular lesion.Together with the periapical film and clinical findings, the diagnosis of VRF could be made. All the extracted teeth showed the VRF. CBCT is helpful to confirm the VRF when using with the conventional periapical film and clinical symptoms.