فهرست مطالب
Journal of Dental Research, Dental Clinics, Dental Prospects
Volume:16 Issue: 3, Summer 2022
- تاریخ انتشار: 1401/11/19
- تعداد عناوین: 10
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Pages 140-146Background
Ki-67 is one of the new biological markers with clinical value in the pathology and prognosis of oral melanoma. It is a nuclear protein involved in regulating cell proliferation. Some studies have suggested an association between Ki-67 and poor survival in patients with oral melanoma. This systematic review was undertaken to clarify this issue.
MethodsDatabases of PubMed, Scopus, and Web of Science were searched using relevant English keywords from 1988 to April 2022. STATA software version 16 and random models were used for meta-analysis.
ResultsEleven articles were included in this systematic review, six of which were selected for meta-analysis. The mean expression of the Ki-67 index in patients with oral melanoma was estimated at 43.81% (28.66‒58.95 with 95% CI, I2=94.2, P<0.001). In addition, the results showed a significant relationship between Ki-67 expression and the prognosis of oral melanoma lesions. Increased expression of this marker weakens the prognosis and decreases the survival rate.
ConclusionHigh expression of Ki-67 may serve as a predictive biomarker for poor prognosis in patients with malignant oral melanoma. Therefore, classifying this malignancy by Ki-67 expression may be considered for therapy regimen selection and integrated management.
Keywords: Ki-67, Meta-analysis, Oral malignant melanoma, Prognosis -
Pages 147-152Background
Temporomandibular disorders have common signs and symptoms, including pain in the masticatory muscles, limitation or deviation in a mandibular range of motion, and other common patient complaints, such as headache and earache. The main focus of this study was to collect comprehensive and integrated data on the effect of the posterior stop on temporomandibular joint disorders, as well as prevention, treatment, and follow-up care for the patients.
MethodsThe authors conducted the search in PubMed, SCOPUS, Web of Science, Cochrane Library, CINHAL, Medline, ProQuest, Google Scholar, Magiran, IranDoc, SID, and Iranmedex databases for relevant articles. A list of selected study sources, related conferences, and grey literature were manually searched in addition to the databases mentioned above. A 21-year time limit was imposed (2000-2021).
ResultsFinally, 16 articles were selected to be reviewed in this systematic review. The designs of the included studies were heterogeneous, and due to the low number of studies covered, the authors could not carry out a meta-analysis.
ConclusionThe causes of temporomandibular disorders are multifactorial and complex. Therefore, it is difficult to investigate the relationship between this disorder and predictors. The results of the present study indicate that to determine the effect of the posterior stop on temporomandibular joint disorders, more clinical trials and case-control studies should be conducted.
Keywords: Dental occlusion, Posterior missing teeth, Prosthodontics, Temporomandibular disorders -
Pages 153-158Background
This study assessed the antimicrobial effects of different concentrations of simvastatin versus triple antibiotic paste (TAP) on Enterococcus faecalis biofilms at different stages of development.
MethodsIn this in vitro study, 70 human single-rooted mature premolars were decoronated, instrumented, and autoclave-sterilized. Next, an E. faecalis suspension was prepared and inoculated into the canals to obtain 4- and 6-week biofilms. After ensuring biofilm formation, the samples in each group were randomly assigned to 5 subgroups (n=12): 1 mg/mL TAP, 10 mg/ mL TAP, 1 mg/mL simvastatin, 10 mg/mL simvastatin, and positive control (phosphate-buffered saline solution). The medicaments were applied in the canals, and the teeth were incubated for one week. Dentin samples were collected by a rotary file, cultured, and the number of E. faecalis colonies was counted. The Kruskal-Wallis, Mann-Whitney U, and Wilcoxon tests were used for data analysis (α=0.05).
ResultsThere were significant differences in colony counts between the two concentrations of TAP and the control group against both 4- and 6-week biofilms (P<0.05). The antibacterial effect of 10 mg/mL TAP and simvastatin was stronger than that of 1 mg/mL concentration against the 4- and 6-week E. faecalis biofilms (P<0.05). Furthermore, 10 mg/mL TAP and simvastatin were more effective against the 4-week biofilms than the 6-week biofilms (P<0.05).
ConclusionAccording to the present results and since biofilms may remain viable in the root canal system for weeks to months, applying 10 mg/mL TAP and simvastatin might be more effective.
Keywords: Enterococcus faecalis, Antibacterial agents, Simvastatin, Root canal preparation -
Pages 159-163Background
Considering the increased use of preheating and novel resin-based materials to restore teeth, the present study investigated the impact of preheating on the flexural strength of a giomer and compared it with a nanohybrid composite resin.
MethodsTwo restorative materials (Beautifil II giomer and Alpha III nanohybrid composite resin) were used. Thirty rod-shaped samples (adding up to 60 samples) were prepared from the materials above and divided into two subgroups: with and without preheating (n=15). Before sample preparation, the giomer and nanohybrid composite resin tubes were preheated at 68ºC for 15 minutes in the preheating subgroups. In the subgroups without preheating, the tubes were kept in a room at 25ºC. Then the flexural strength was compared between the two groups with two-way ANOVA at a significance level of P<0.05.
ResultsThe results showed significantly higher flexural strength in the preheated subgroups than in the non-preheated subgroups (P<0.001). In addition, the mean flexural strength values were significantly higher in the giomer groups than in the nanohybrid composite resin groups (P<0.001).
ConclusionPreheating increased the studied materials’ flexural strengths significantly. The flexural strength of the giomer restorative material was higher than that of the nanohybrid composite resin, irrespective of preheating.
Keywords: Composite resins, Dental restoration, Flexural strength, Heating -
Pages 164-169Background
An accurate diagnosis of vertical skeletal abnormalities presents several challenges. Specific cephalometric parameters can be effectively used for this purpose; however, the diagnostic accuracy of these parameters has not been entirely ascertained. This study examines the effectiveness of two novel cephalometric parameters for diagnosing vertical dysplasia.
MethodsIn this retrospective study, orthodontic patients were distributed into three study groups: average growth (AGG), horizontal growth (HGG), and vertical growth (VGG). The efficacies of the sum of angles (maxillary, mandibular, and ramal) and the height ratio (lower anterior facial height [LAFH]/upper anterior facial height [UAFH]) in identifying different growth patterns were examined. Receiver operating characteristic (ROC) curves were employed to assess the diagnostic precision quantitatively.
ResultsA total of 150 patients were included and divided equally among the three study groups. The ramal and mandibular angles varied across AGG, HGG, and VGG; however, the maxillary angle and the sum of these three angles did not vary significantly. There was a substantial variance in LAHF, UAHF, and their ratio in the three groups. The height ratio had 88% and 92% sensitivity to diagnose VGG and HGG, with cut-off values of 46 and 34, respectively (P<0.001).
ConclusionHeight ratio values varied considerably depending on the facial growth patterns, suggesting its efficacy as a diagnostic tool for skeletal dysplasia, with greater reliability for positive treatment outcomes.
Keywords: Cephalometry, Dysplasia, Mandible, Maxilla, Orthodontics -
Pages 170-178Background
New surface treatments have been proposed to expand the clinical indications of zirconia prostheses. This study aimed to evaluate the effect of silica and fluorine nanofilms on zirconia ceramic on the resin cement bond strength.
MethodsZirconia blocks and discs underwent different surface treatments: untreated zirconia (CON), sandblasted, silica-coated alumina particles (30 µm) (SC), silica nanofilm (SN), and fluorine nanofilm (FN). Nanofilm deposition was performed through plasma enhanced chemical vapor deposition (PECVD). Zirconia surfaces were characterized on disks by morphology (atomic force microscopy, AFM), chemical analysis (x-ray photoelectron spectroscopy, XPS), and contact angle analysis. A silane coupling agent was applied on each treated surface, and a cylinder of resin cement was built up. Half of the specimens in each group were submitted to 6000 thermal cycles (TC). Bond strength was analyzed using the shear test, and the fractographic analysis was performed with stereomicroscopy and SEM/EDS. Statistical analysis was performed through one-way ANOVA and Tukey test in the non-aged and aged specimens.
ResultsNanofilms modified the zirconia surface, which became more hydrophilic and chemically reactive. Chemical bonding between Si-O was found in SN, and FN promoted a fluorination process on the ceramic surface, converting zirconia into zirconium oxyfluoride. Specimens of the SN (TC) group failed on pre-testing. FN (TC) bond strength (3.8 MPa) was lower than SC (TC) and CON (TC) after shearing. Adhesive failure predominated in the experimental groups. Silica nanofilm failure occurred after aging.
ConclusionSilica and fluorine nanofilms deposited by PECVD did not promote effective bonding between zirconia and resin cement.
Keywords: Bonding, Fluorine, Nanofilm, Shear Test, Silicon, Zirconia -
Pages 179-185Background
In recent years, complete denture construction has been revolutionized using computer-aided designing and computer-aided manufacturing (CAD-CAM) technology. This clinical study compared the retention and denture base adaptation of 3D-printed complete dentures fabricated using dimethacrylate-based resins with a photoinitiator versus conventional complete dentures.
MethodsTen completely edentulous patients were nominated for this study. Each patient received two complete dentures. One complete denture was conventionally fabricated, while the other was digitally fabricated through 3D printing of dimethacrylate-based resins with a photoinitiator. Denture base adaptation for both dentures was evaluated using surface matching software. Denture retention was also evaluated using a digital force meter at the time of complete denture insertion (T0 ), after three months (T3 ) and six months (T6 ) of denture use.
ResultsRegarding adaptation (mean misfit values), a statistically insignificant difference was detected between the two differently fabricated complete dentures. In addition, comparable satisfactory retention values were observed for both conventionally fabricated and 3D-printed dentures; however, there was an insignificant increase in retention over time.
Conclusion3D-printed complete dentures fabricated using dimethacrylate-based resins could be a promising alternative to conventionally fabricated complete dentures with satisfactory denture base adaptation and retention.
Keywords: 3D printing, CAD-CAM, Complete dentures, Denture retention -
Pages 186-189Background
Studies have shown a significant relationship between the width and thickness of keratinized gingiva around the implant and changes in marginal bone level, with a significant effect on the health and esthetic of tissues around the implant, especially in the anterior region of the maxilla, which is an esthetic area.
MethodsTen patients referring to the Faculty of Dentistry seeking implant placement in the anterior maxilla were included in the study. The connective tissue of the palatal gingiva of the surgical site was folded to the buccal aspect with the buccal base, and the thickness and width of keratinized gingiva around the buccal surface of each implant were measured in three time intervals, including before surgery and 6 and 12 weeks after surgery. Based on the results of the Kolmogorov-Smirnov test, Friedman test and repeated-measures ANOVA were used to analyze the data.
ResultsThe intervention significantly affected changes in the gingival thickness. After the intervention, gingival thickness significantly increased compared to the baseline (P<0.05). The results also showed that the intervention did not significantly affect the width of keratinized gingiva. The width of keratinized gingiva at baseline was not significantly different from the two time intervals after intervention (P>0.05).
ConclusionBuccal-based modified palatal flap in anterior maxillary implants increased the thickness of keratinized gingiva, with no significant effect on the keratinized gingiva width.
Keywords: Dental implant, Gingiva, Peri-implantitis -
Pages 190-195Background
Microbial accumulation is still a significant problem with removable acrylic appliances. This study aimed to assess the antimicrobial properties of a self-cured acrylic resin containing curcumin nanoparticles (CNPs).
MethodsThis in vitro study used 48 acrylic discs containing 0.5%, 1%, and 2% CNPs. The antimicrobial properties of the discs against Streptococcus mutans, Streptococcus sanguinis, Lactobacillus acidophilus, and Candida albicans were evaluated using disc agar diffusion (DAD), eluted component, and biofilm inhibition tests. The growth inhibition zones were measured, and the colonies were counted after 1, 3, and 7 days.
ResultsDAD test showed that none of the curcumin nanoparticle concentrations caused growth inhibition zones for any microorganisms. All the concentrations were effective against all four microorganisms in the biofilm inhibition test except 0.5% for L. acidophilus. In the eluted component test, solutions containing 2% concentration had maximum growth inhibition of all the groups at all time intervals. An increase in curcumin nanoparticle concentration from 0.5% to 1% was effective only against C. albicans.
ConclusionGenerally, CNPs in all concentrations were effective against the biofilms of all four microorganisms assessed in this study. Therefore, incorporating 2% CNPs into acrylic resin seems suitable for clinical use.
Keywords: Acrylic resin, Antimicrobial, Curcumin, Nanoparticles, Poly (methyl methacrylate) -
Pages 196-203Background
Chemical agents, in combination with mechanical methods, play an important role in reducing microbial plaque on denture surfaces. However, these methods might change the mechanical behavior of acrylic resins, including microhardness and surface roughness. This in vitro study investigated the effect of two disinfectants, i.e., water and sodium hypochlorite, on the microhardness of conventional heat-cured and TiO2 nanoparticle-reinforced acrylic resins.
MethodsSixty acrylic resin specimens were divided into two groups, and the samples in each group were randomly assigned to three subgroups (n=10). Heat-cured specimens and 1 wt% TiO2 acrylic resin were prepared and immersed in three solutions: water, a solution prepared with NatureDent pills, and 1% sodium hypochlorite for 30, 60, and 90 days. Microhardness tests were performed on each sample at each immersion stage. The data were analyzed using descriptive statistical methods, three-way and one-way ANOVA, repeated-measures t test, and Tukey HSD tests using SPSS 17. P values<0.05 were considered significant.
ResultsAll three independent parameters, including resin, solution, and time, significantly affected microhardness (P<0.05). The microhardness of both specimen types, i.e., conventional heat-cured and TiO2 nanoparticle-reinforced acrylic resins, immersed for 30, 60, and 90 days, was the highest and lowest in water and hypochlorite solutions, respectively. Regarding 90 days, the microhardness values of conventional heat-cured and TiO2 nanoparticle-reinforced acrylic resins were 17.050±0.094 and 19.953±0.053 in water, 15.675±0.069 and 18.965±0.037 in hypochlorite, and 16.713±0.122 and 19.39±20.113 in NatureDent solutions, respectively.
ConclusionDisinfecting two types of acrylic resin specimens decreased their microhardness as a function of immersion time for up to 90 days in the three solutions. However, the magnitude of hardness lost was less for TiO2 nanoparticles-reinforced acrylic resin.
Keywords: Denture, Heat-cured acrylic resin, Microhardness, TiO2 nanoparticles