PMCC PMCC

Search tips
Search criteria

Advanced

Important Notice

PubMed Central Canada to be taken offline in February 2018

On February 23, 2018, PubMed Central Canada (PMC Canada) will be taken offline permanently. No author manuscripts will be deleted, and the approximately 2,900 manuscripts authored by Canadian Institutes of Health Research (CIHR)-funded researchers currently in the archive will be copied to the National Research Council’s (NRC) Digital Repository over the coming months. These manuscripts along with all other content will also remain publicly searchable on PubMed Central (US) and Europe PubMed Central, meaning such manuscripts will continue to be compliant with the Tri-Agency Open Access Policy on Publications.

Read more

Results 1-25 (790)
 

Clipboard (0)
None

Select a Filter Below

Journals
Year of Publication
more »
1.  Guided tissue regeneration and platelet rich growth factor for the treatment of Grade II furcation defects: A randomized double-blinded clinical trial - A pilot study 
Dental Research Journal  2017;14(6):363-369.
Background:
The treatment of furcation area defects remained as a challenging issue in periodontal treatments. Regeneration treatment of furcation defects is the most discussed periodontal treatment. Although not completely hopeless in prognosis, the presence of the furcation involvement significantly increases the chance of tooth loss. The current research was conductedeto compare theeadditive effect of combined guided tissue regeneration (GTR) and platelet-rich growth factor (PRGF) on the treatment of furcation bony defects.
Materials and Methods:
A randomized, triple-blinded, split-mouth study was designed. It included patients with a moderate to severe chronic periodontitis with bilateral Grade II furcation involvement of first or second mandibular molars. Each side of mouth was randomly allocated for the treatment with either Bio-Gide American Society of Anesthesiologists GTR or a PRGF or PRGF by itself. Plaque index, gingival index, vertical clinical attachment level, vertical probing depth, recession depth (REC), horizontal probing depth, fornix to alveolar crest (FAC), fornix to base of defect (FBD), furcation vertical component and furcation horizontal component (FHC) were recorded. The current research was conducted to compare the additive effect of combined GTR and PRGF on treatment of furcation bony defects. Altman's nomogram, Kolmogorov–Smirnov test, Friedman test, general linear model, repeated measures, and paired t-test were used as statistical analysis in this research. P < 0.05 was considered statistically significant.
Results:
Eight patients were finally enrolled for this study. Overly, general and specific clinical and furcation parameters were improved except REC that was deteriorated insignificantly and FAC improved not significantly. Intergroup comparison revealed better improvement of FHC in GTR/PRGF group (P = 0.02).
Conclusion:
A significant improvement in the Grade II furcation defects treated with either GTR or PRGF/GTR was noticed. Further large-scale trials are needed to reveal differences of mentioned treatment in more details.
PMCID: PMC5713058
Bioengineering; guided tissue regeneration; platelet-Rich plasma; tooth; furcation
2.  Zygoma implants in oral rehabilitation: A review of 28 cases 
Dental Research Journal  2017;14(6):370-375.
Background:
The functional and esthetic rehabilitation of patients with atrophic maxilla or posterior maxillary defect is often challenging. The aim of this study was to determine patient demographics, indications, success rate, and complications following the use of zygoma implants.
Materials and Methods:
All patients who had zygoma implant placement in our clinic between 1998 and 2013 were retrospectively assessed for implant outcome. Data were analyzed using Statistical Package for the Social Sciences (SPSS) version 16 and Microsoft Excel 2007 test for significance (ρ) using Pearson's Chi-square (χ2) set at 0.05.
Results:
A total of 28 patients consisting of 22 females (78.6%) and 6 males (21.4%) were treated, and their age ranged from 41 years to 83 years with a mean age of 60.3 ± 10.6 years. The main indication for zygoma implant placement was atrophic maxilla 12 (42.9%). In the prosthetic rehabilitation of the patients, 2 had epithetic prostheses, and 2 had obturators while 18 patients had conventional removable dental prostheses. Four patients (14.3%) had perimplantitis and one implant was accidentally placed into the maxillary sinus. A cumulative success rate of 88.1% was obtained from this retrospective analysis.
Conclusion:
A cumulative success rate of 88.1% reported in this study is lower than the reports from other studies. The difference in success rates may be related to different criteria for assessment of zygoma implant success and to the difference in inclusion criteria and follow-up period.
PMCID: PMC5713059
Maxilla; prostheses and implants; rehabilitation
3.  Allergic rhinitis and dental caries in preschool children 
Dental Research Journal  2017;14(6):376-381.
Background:
Allergic rhinitis (AR) may be overdocumented in cases of dental caries because of controversies in the literature This study was conducted to investigate the potential relationship between AR and dental caries in children.
Materials and Methods:
A total of 296 children were included in this cross-sectional study. Participants were evaluated using the decay-missing-filled (DMF) index, and their AR status was evaluated by physical examination and through a standard questionnaire. Baseline demographics and clinical characteristics were compared among groups using Student's t-test or the Mann–Whitney U-test, the Chi-square test, and/or Fisher's exact test as appropriate. A level of P < 0.05 was regarded as statistically significant.
Results:
Evidence of AR was found in 77 (35.1%) participants. There was no significant difference in the rate of tooth decay or DMF between participants with or without AR (P = 0.07), but a significant difference was observed in the number of missing and filled teeth between those with and without AR (P < 0.05). There were no significant differences in educational level, family income, milk intake, use of pacifier, use of a toothbrush, saliva secretion, or body mass index (P > 0.05 in all cases) between AR-positive and AR-negative patients. Fluoride therapy and oral breathing were identified as confounding factors and controlled using log-linear analysis. The mean rate of DMF in patients who also had AR was 20% greater than in the AR-negative group (odds ratio [OR] = 1.21, confidence interval [CI]: 1.05–1.35) and 15% greater in among children who breathed orally than those who did not (OR = 1.15 CI: 1.02–1.31).
Conclusion:
AR and oral breathing may have an effect on oral health and dental condition, leading to an increased rate of tooth loss, oral fillings, and development of dental caries.
PMCID: PMC5713060
Rhinitis Allergic; dental caries; dental filling; mouth breathing
4.  The effect of different root canal sealers on the fracture resistance of endodontically treated teeth-in vitro study 
Dental Research Journal  2017;14(6):382-388.
Background:
The aim of this study was to compare the in vitro effects of four different root canal sealers on the fracture resistance of endodontically treated teeth.
Materials and Methods:
Seventy-five freshly extracted human mandibular premolars were used for the study. Teeth were divided into five groups based on type of root canal sealers used. Gutta-percha was used for all the samples: Group I: AH Plus root canal sealer, Group II: MTA Fillapex root canal sealer, Group III: Apexit root canal sealer, Group IV: Conventional zinc oxide-eugenol (ZOE) sealer, Group V: Control (unobturated teeth). The teeth were embedded in acrylic resin blocks and fracture force was measured using a universal testing machine (Asian Test Equipments). Data obtained were statistically evaluated using one-way ANOVA and post hoc test (Tukey's test). All groups showed statistically significant result (P < 0.05).
Results:
Group I and Group II showed higher resistance to fracture than other three groups. There was comparable difference in fracture force between Group I and Group II. Moreover, there was no statistically significant difference between Group III and Group IV and between Group IV and Group V.
Conclusion:
Based on this in vitro study, resin-based sealer was more effective as compared to other sealers and the control group. However, no significant differences were observed between ZOE and control group.
PMCID: PMC5713061
Sealer; fracture; resistance; MTA- Fillapex; zinc oxide-eugenol
5.  Masking ability of a zirconia ceramic on composite resin substrate shades 
Dental Research Journal  2017;14(6):389-394.
Background:
Masking ability of a restorative material plays an important role to cover discolored tooth structure; however, this ability has not yet been well understood in zirconia-based restorations. This study assessed the masking ability of a zirconia ceramic on composite resin substrates with different shades.
Materials and Methods:
Ten zirconia disc specimens, with 0.5 mm thickness and 10 mm diameter, were fabricated by a computer-aided design/computer-aided manufacturing system. A white substrate (control) and six composite resin substrates with different shades including A1, A2, A3, B2, C2, and D3 were prepared. The substrates had a cylindrical shape with 10 mm diameter and height. The specimens were placed onto the substrates for spectrophotometric evaluation. A spectrophotometer measured the L*, a*, and b* values for the specimens. ΔE values were calculated to determine the color differences between the groups and the control and then were compared with a perceptional threshold (ΔE = 2.6). Repeated measures ANOVA and Bonferroni tests were used for data analysis (P < 0.05).
Results:
The mean and standard deviation of ΔE values for A1, A2, A3, B2, C2, and D3 groups were 6.78 ± 1.59, 8.13 ± 1.66, 9.81 ± 2.64, 9.61 ± 1.38, 9.59 ± 2.63, and 8.13 ± 1.89, respectively. A significant difference was found among the groups in the ΔE values (P = 0.006). The ΔE values were more than the perceptional threshold in all the groups (P < 0.0001).
Conclusion:
Within the limitations of this study, it can be concluded that the tested zirconia ceramic could not thoroughly mask different shades of the composite resin substrates. Moreover, color masking of zirconia depends on the shade of substrate.
PMCID: PMC5713062
Color; spectrophotometry; visual perception; ceramic
6.  Association of macrophage migration inhibitory factor gene polymorphisms with chronic periodontitis in a South Eastern Iranian population 
Dental Research Journal  2017;14(6):395-402.
Background:
Macrophage migration inhibitory factor (MIF) is a key proinflammatory mediator. It plays a vital role in immune response against the oral disease. MIF is a regulator of innate immunity, and bacterial antigens can stimulate serum level of this protein. In experimental gingivitis, the expression level of MIF increases and this increment positively correlates with oral plaque index. The single nucleotide polymorphisms in the gene encoding the MIF protein can control the function of MIF. The aim of the present study was a clarification of the associations between MIF-173 G/C, MIF 95 bp, and 189 bp insertion/deletion (I/D) polymorphisms and chronic periodontitis (CP) compared with healthy controls.
Materials and Methods:
This case–control study was carried out on 210 CP patients and 100 normal subjects. MIF-173 G/C and MIF 95 bp and 189 bp I/D polymorphisms were genotyped, using polymerase chain reaction–restriction fragment-length polymorphism (PCR-RFLP) and PCR, respectively. Allele and genotype frequencies of the variants were compared between patients and controls using Chi-square. test. The value of P < 0.05 was considered statistically significant.
Results:
The study findings showed that MIF-173 G/C polymorphism, especially the C allele increased the risk of CP. The 95-bp I/D polymorphism was not associated with CP and the 185-bp I/D variant was not polymorphic in our population.
Conclusion:
Therefore, MIF-137 G/C variant increased the risk of CP in the South East of the Iranian population. In other words, polymorphisms in MIF gene influence clinical outcome of CP infection and influence the susceptibility to disease. Further studies with larger sample sizes and different ethnicities are required to validate our findings.
doi:10.4103/1735-3327.218563
PMCID: PMC5713063
Chronic periodontitis; gene; Macrophage Migration-Inhibitory Factors; migration inhibitory factor; polymorphism
7.  Correlation of Vitamin D status and orthodontic-induced external apical root resorption 
Dental Research Journal  2017;14(6):403-411.
Background:
Adequate Vitamin D is essential for dental and skeletal health in children and adult. The purpose of this study was to assess the correlation of serum Vitamin D level with external-induced apical root resorption (EARR) following fixed orthodontic treatment.
Materials and Methods:
In this cross-sectional study, the prevalence of Vitamin D deficiency (defined by25-hydroxyvitamin-D) was determined in 34 patients (23.5% male; age range 12–23 years; mean age 16.63 ± 2.84) treated with fixed orthodontic treatment. Root resorption of four maxillary incisors was measured using before and after periapical radiographs (136 measured teeth) by means of a design-to-purpose software to optimize data collection. Teeth with a maximum percentage of root resorption (%EARR) were indicated as representative root resorption for each patient. A multiple linear regression model and Pearson correlation coefficient were used to assess the association of Vitamin D status and observed EARR. P < 0.05 was considered statistically significant.
Results:
The Pearson coefficient between these two variables was determined about 0.15 (P = 0.38). Regression analysis revealed that Vitamin D status of the patients demonstrated no significant statistical correlation with EARR, after adjustment of confounding variables using linear regression model (P > 0.05).
Conclusion:
This study suggests that Vitamin D level is not among the clinical variables that are potential contributors for EARR. The prevalence of Vitamin D deficiency does not differ in patients with higher EARR. These data suggest the possibility that Vitamin D insufficiency may not contribute to the development of more apical root resorption although this remains to be confirmed by further longitudinal cohort studies.
PMCID: PMC5713064
25-Hydroxycalciferol; orthodontics; root resorption; Vitamin D
8.  Static and kinetic frictional forces of silica-insert ceramic brackets with coated archwires in artificial saliva 
Dental Research Journal  2017;14(6):412-417.
Background:
During sliding mechanics, the frictional force (FF) is an important counterforce to orthodontic tooth movement. The purpose of this in vitro study was to investigate the static and kinetic FFs of S silica-insert ceramic (SIC) brackets with Teflon-coated (TC) and conventional S stainless steel (SS) archwires.
Materials and Methods:
The target group of this study included 80 maxillary canine 0.022 inch slot SIC brackets. Forty SS brackets were used as the control. TC and conventional uncoated SS archwires of different dimensions (0.016, 0.018, 0.016 × 0.022, and 0.018 × 0.025 inch) were examined. All tests were carried out under artificial saliva injected condition. Scanning Electron Micrographs were prepared for two samples of coated and uncoated archwires. Analysis of variance and Tukey post hoc tests were used for statistical purposes (level of significance P < 0.05).
Results:
SIC brackets showed significantly lower levels of FFs than SS brackets. TC archwires had greater frictional values than conventional uncoated ones. They also exhibited an unusual behavior of increasing kinetic FFs with time. Indentation and delamination of coating were obvious under scanning electron microscopy observations.
Conclusion:
From the standpoint of friction, SIC brackets may serve well, even better than SS brackets, in sliding mechanics. The coating layer of the archwires may delaminate and lost, causing an impediment to tooth movement.
PMCID: PMC5713065
Artificial; Friction; orthodontic bracket; saliva
9.  Assessment of the anterior loop of mental nerve in an Iranian population using cone beam computed tomography scan 
Dental Research Journal  2017;14(6):418-422.
Background:
The anterior loop is an important structure in the interforaminal area of the mandible. The aim of the present study was to assess the prevalence and length of the anterior loop of mental nerve using cone beam computed tomography (CBCT) scan and to compare the differences between age, gender, and side.
Materials and Methods:
A total of 180 projections were analyzed in different sectional planes. The inferior alveolar nerve was determined. To measure the length of anterior loop in tangential plane, two parallel lines from the anterior point of mental foramen and anterior point of anterior loop were drawn. The distance between these two lines was measured by drawing a perpendicular line on them. The data were analyzed by SPSS (version 22). McNemar's test, Chi-square test, and t-test were performed to compare the significance of findings regarding side, age, and gender. P < 0.05 was considered statistically significant.
Results:
The results showed that 32.8% of images had anterior loop. The mean lengths of anterior loop in the right and left sides were 2.69 mm (standard deviation [SD] = 1.56) and 2.36 mm (SD = 1.16), respectively. There were no statistically significant differences between the mean lengths of the anterior loop in both sides (P = 0.18).
Conclusion:
Great care is required when placing implants in proximity to mental foramen to avoid anterior loop injury. Because of the variations of anterior loop length in each patient, a fixed distance anterior to the mental foramen is not safe, and the anterior loop length should be determined for each individual. The use of CBCT provides accurate measurements of the length of anterior loop.
PMCID: PMC5713066
Anterior loop of the inferior alveolar nerve; cone beam computed tomography-scan; implant
10.  A case of central mucoepidermoid carcinoma associated with dentigerous cyst 
Dental Research Journal  2017;14(6):423-426.
Mucoepidermoid carcinoma (MEC) is the most common malignant salivary gland neoplasm. Central MEC (CMEC) is a rare primary intraosseous bony lesion with an incidence of 2%–4.3% of all MECs reported. In this article, we present a rare case of a CMEC in the anterior region of maxilla at a 43-year-old female patient that was arising from a dentigerous cyst. CMECs are extremely rare tumor. They are usually low-grade lesions with favorable prognosis. Odontogenic cysts are one of the origins of this lesion. Treatment of impacted tooth is necessary in the early stage for prevention of this neoplasm.
PMCID: PMC5713067
Dentigerous cyst; malignant; mucoepidermoid carcinoma
12.  The clinical and metabolic effects of subgingival application of xanthan-based chlorhexidine gel in Type 2 diabetic patients with chronic periodontitis 
Dental Research Journal  2017;14(5):299-305.
Background:
There is a two-way relationship between periodontal disease and diabetes. The purpose of this study was to evaluate the clinical and metabolic effects of a xanthan-based chlorhexidine (CHX) gel used as an adjunct to nonsurgical periodontal therapy in Type II diabetic patients with chronic periodontitis.
Materials and Methods:
Sixty-eight diabetic patients with moderate to advanced periodontitis and glycated hemoglobin (HbA1c) ≥6% were selected. The test group (n = 34) received scaling and root planning (SRP) plus xanthan-based CHX gel. The control group (n = 34) received single SRP. Fasting blood sugar (FBS) and HbA1c tests were done at the baseline and after 3 and 6 months. Data from the study were analyzed using descriptive statistics (mean ± standard deviation and frequency), ANOVA test by SPSS.15 software (SPSS Inc. Chicago, IL, USA). P < 0.05 was considered statistically significant.
Results:
Patients in test group exhibited a decrease in FBS from the baseline (227 ± 64.97) to the 3 and 6 months follow-up (208 ± 61.95 and 201 ± 61.33; P < 0.001). HbA1cb levels decreased from 7.72 ± 0.99 to 6.20 ± 0.97 and 6.06 ± 1.04 after 3 and 6 months follow-up (P < 0.001), respectively. Reduction of FBS and HbA1c was statistically significant after 3 and 6 months in the control group (P < 0.001).
Conclusion:
Considering the limitations of this study, the application of CHX gel might improve the effects of nonsurgical periodontal treatment in diabetic patients with periodontitis.
PMCID: PMC5654223
Chlorhexidine; chronic periodontitis; glycated hemoglobins; scaling; root planing; diabetes mellitus Type 2
13.  Selective nitric oxide synthase inhibitor promotes bone healing 
Dental Research Journal  2017;14(5):306-313.
Background:
Nitric oxide (NO) has many functions in wound healing and bone metabolism. This study sought to assess the local effect of aminoguanidine (AG), a selective inducible NO synthase (iNOS) inhibitor, on the rate of bone healing.
Materials and Methods:
This experimental interventional study was conducted on 36 rats, which were randomly divided into three groups of control, placebo, and AG. Bone defects measuring 5 mm × 5 mm were created in the femur. In control group, bone defects remained empty. A placebo gel was applied to defects in the placebo group. AG gel was placed in bone defects in AG group. New bone formation and healing were assessed using histological and histomorphometric analyses. The healing score and the percentage of new bone formation (total bone mass, immature bone, and mature bone) were compared among the three groups using the Kruskal–Wallis test and analysis of variance, respectively. A P < 0.05 was statistically significant.
Results:
The mean healing score in AG group (3.17 ± 0.577) was significantly higher than that in control (2.67 ± 0.49) and the placebo (2.58 ± 0.515) groups (P = 0.036). The percentage of new mature (lamellar) bone in AG group (22.06 ± 1.90) was significantly higher than that in control (20.94 ± 2.03) and the placebo (20.53 ± 1.20) groups (P = 0.008).
Conclusion:
The rate of bone healing was faster in the AG compared to the other two groups. Local application of selective iNOS inhibitors like AG may be efficient as an adjunct in the clinical setting where local bone formation is required.
PMCID: PMC5654224
Aminoguanidine; bone; healing; nitric oxide; nitric oxide synthase
14.  Evaluation of myofibroblasts in oral submucous fibrosis and oral squamous cell carcinoma: The pathogenesis and correlation 
Dental Research Journal  2017;14(5):314-320.
Background:
Oral submucous fibrosis (OSMF) is a chronic debilitating disease of the oral cavity having premalignant potential and unclear pathogenesis. Recently, myofibroblast has been postulated to play an important role in its pathogenesis and in the process of carcinogenesis. The purpose of this study was to evaluate and compare the presence of myofibroblasts in normal mucosa, different grades of OSMF, and oral squamous cell carcinoma (OSCC).
Materials and Methods:
The present in vitro cross-sectional descriptive study sample consisted of three groups, including 40 OSCCs, 40 OSMF, and 10 sections of normal oral epithelium taken as control group. Alpha-smooth muscle actin was used to identify myofibroblasts using immunohistochemical technique. P < 0.05 was taken as statistically significant.
Results:
The presence of myofibroblasts was significantly higher in OSMF cases when compared with normal epithelium specimens. The presence of myofibroblasts was significantly higher in OSCC compared to OSMF cases. A significant difference was not observed between the different grades of OSCC.
Conclusion:
These findings favor the possibility that OSMF actually represents an abnormal healing process in response irritation caused by areca nut. A significant increase in myofibroblasts in OSCC as compared to OSMF also highlights the possible role it may play in the malignant transformation of OSMF.
PMCID: PMC5654225
Alpha-smooth muscle actin; myofibroblast; oral squamous cell carcinoma; oral submucous fibrosis
15.  Comparative evaluation of root canal morphology of mandibular premolars using clearing and cone beam computed tomography 
Dental Research Journal  2017;14(5):321-325.
Background:
Different techniques are used to evaluate the anatomy of root canal system. The present study was aimed to evaluate the root canal morphology of mandibular premolars using clearing and cone beam computed tomography (CBCT) techniques.
Materials and Methods:
A total of 182 mandibular first and second premolars were evaluated in vitro using 100 μm CBCT cross sections. The root canal morphology of the teeth was determined based on Vertucci classification in relation to the prevalence of C-shaped canals, lateral canals, and furcation location. Having removed the pulp tissue with NaOCl solution and staining the root canals with India ink, the samples were decalcified with 5% nitric acid and dehydrated with isopropyl alcohol. Finally, the samples were cleared with methyl salicylate. Data were analyzed by SPSS 16 software using McNamara, t-test, and Kappa coefficient.
Results:
After Type I, the most frequent morphologies in both first and second premolars were Type V followed by Type IV. The prevalence rates of C-shaped morphology in first premolars using clearing and CBCT were 4.4% and 6.6%, respectively. However, no C-shaped morphology was found in second premolars. The maximum and minimum levels of agreement between the two techniques were observed in Type IV and Type V root canal morphologies, respectively. Extra root canals were identified in 25% and 13% of the first and second premolars, respectively.
Conclusion:
CBCT showed a higher accuracy in determining C-shaped root canal morphology than the clearing technique. It also showed the least accuracy in diagnosing lateral root canals.
PMCID: PMC5654226
Clearing; technique; cone beam computed tomography; root canal; morphologhy
16.  Effect of finishing/polishing techniques and time on surface roughness of esthetic restorative materials 
Dental Research Journal  2017;14(5):326-330.
Background:
Surface roughness associated with improper finishing/polishing of restorations can result in plaque accumulation, gingival irritation, surface staining, and poor esthetic of restored teeth. The study aimed to evaluate the efficiency of various finishing and polishing systems and time using various procedures on surface roughness of some esthetic restorative materials.
Materials and Methods:
In this in vitro study, samples of two composite materials, compomer and glass ionomer cement (GIC) materials, were fabricated. Finishing and polishing were done immediately (n = 40) and after 1 week (n = 40) using four systems (diamond bur + soflex discs; diamond bur + Astropol polishing brush; tungsten carbide bur + soflex discs; tungsten carbide bur + Astropol polishing brush). Surface roughness was measured using surface profilometer. Data were statistically analyzed by t-test (for each material and time period) and one-way analysis of variance followed by Tukey's post hoc (for finishing and polishing systems) at a significant level of P < 0.05.
Results:
Analysis of time period, irrespective of finishing and polishing system showed that Ra values were greater (P < 0.05) in delayed polishing in GIC > Z100 > Filtek P90 > Dyract AP, suggesting immediate polishing is better. Among the materials, Filtek P90 had the least Ra values indicating the smoothest surface among all materials, followed by Z100, Dyract AP, and GIC. Comparison of polishing and finishing systems irrespective of materials showed that Ra values were lower (P > 0.05) in diamond + Astropol combination whereas diamond + soflex had the greatest Ra values.
Conclusion:
It might be concluded that: (i) Filtek P90 showed least Ra values followed by < Z100 < Dyract < GIC; (ii) immediate (24 h) finishing/polishing of materials is better than delayed; and (iii) among all these polishing systems, diamond bur–Astropol and Astrobrush showed good surface finish.
PMCID: PMC5654227
Artglass dental composits; dental esthetic; material; dental finishing; dental polishing
17.  Do increased drilling speed and depth affect bone viability at implant site? 
Dental Research Journal  2017;14(5):331-335.
Background:
The aim of this study was to assess the effect of increasing the drilling speed and depth during implant site preparation on bone viability.
Materials and Methods:
In this prospective cohort study, participants were divided into four groups based on the speed and depth of drilling at the first molar site in the mandible. Participants underwent drilling at Group 1: 1000 rpm and 10 mm depth, Group 2: 1500 rpm and 10 mm, Group 3: 1000 rpm and 13 mm, and Group 4: 1500 rpm and 13 mm. Obtained specimens were assessed histologically to the qualitative measurement of bone viability, and the percentage of vital bone were evaluated by histomorphometric analysis. ANOVA was used to compare age and the mean percentage of vital bone and Tukey's test as post hoc was applied for pairwise comparison of groups.
Results:
A total of 100 participants were studied in four groups (25 subjects in each group). Histological evaluation revealed a low level of bone viability maintenance in all groups. Histomorphometric analysis showed the mean percentage of vital bone was 9.5 ± 3.91% in Group 1, 8.86 ± 3.84% in Group 2, 8.32 ± 3.80% in Group 3, and 4.27 ± 3.22% in Group 4. A significant difference was noted in the mean percentage of bone viability among the four groups (P = 0.001).
Conclusion:
It seems that increasing the drilling speed or depth during dental implant site preparation does not affect the mean percentage of cell viability, while the increase in both depth and speed may decrease the percentage of viable cells.
PMCID: PMC5654228
Bone; vitality; dental implant; drilling
18.  Push-out bond strength of different intracanal posts in the anterior primary teeth according to root canal filling materials 
Dental Research Journal  2017;14(5):336-343.
Background:
This study was carried out to evaluate the effect of root canal filling on the bond strength of three intracanal posts in the primary incisors.
Materials and Methods:
Sixty primary incisors were prepared and then divided into two groups (n = 30). The first group canals obturated with zinc oxide eugenol (ZOE) and Group 2 canals obturated with Metapex. Further, the two group categories were divided into three subgroups (n = 10): (1) short composite post (SCP), (2) glass fiber posts (GFPs) cemented with flowable composite, and (3) GFP with glass ionomer cement (GFP + GIC). The push-out test was performed with a universal testing machine. The results were statistically analyzed with two-way analysis of variance.(α = 0.05).
Results:
The mean bond strength of the first group obturated with ZOE was lower than that of the second group obturated with Metapex (P = 0.046). Moreover, from a statistical point of view, in all three subgroups, the correlation of mean push-out bond strength between SCP and GFP coated with flowable composite was not substantial at P = 0.97. However, the mean bond strength of SCP was in fact significantly greater than that of the GFP coated with GIC since P = 0.034.
Conclusion:
Using ZOE resulted in the significant reduction of the mean bond strength of the intracanal posts when utilized in the primary anterior teeth. Likewise, SCP and GFP coated with flowable composite showed higher push-out bond strengths for restoring primary anterior teeth.
PMCID: PMC5654229
Composite dental resin; Metapex; post and core technique; primary tooth; zinc oxide eugenol cement
19.  Microbial microleakage assessment of class V cavities restored with different materials and techniques: A laboratory study 
Dental Research Journal  2017;14(5):344-350.
Background:
The aim of this study was to compare microbial microleakage of class V cavities restored with different materials and techniques using a microbial leakage assessment method.
Materials and Methods:
One hundred extracted, caries-free, human maxillary premolars were randomly divided into five groups. Group 1: Resin-modified glass ionomer (RMGI), Group 2: Closed sandwich with flowable composite + nanohybrid composite, Group 3: Nanohybrid composite, Group 4: Closed sandwich with RMGI + nanohybrid composite, and Group 5: Flowable composite + nanohybrid composite that were co-cured together (“snow-plow” technique). A microbial penetration method utilizing Streptococcus mutans as an indicator was tested for leakage assessment. Data were analyzed and the significance level was α =0.05.
Results:
The log-rank test indicated a statistically significant difference in leakage rates among the five groups (P = 0.008). Mantel–Cox log-rank test indicated statistically significant differences in microleakage rates between Groups 1 and 3 (P = 0.029), between Groups 2 and 5 (P = 0.005), and between Groups 3 and 5 (P = 0.002).
Conclusion:
With respect to the limitations of an in vitro study, our findings suggest that adding a thin layer of flowable composite or RMGI under nanohybrid composite in class V cavities did not decrease the bacterial leakage rate, whereas use of the “snow-plow” technique caused an increase in the microleakage rate.
PMCID: PMC5654230
Dental leakage; Dental restoration; Filtek Z250 composite resin; fuji glass- inomer lining cement
20.  The relation of preoperative stress and anxiety on patients' satisfaction after implant placement 
Dental Research Journal  2017;14(5):351-355.
Background:
There are some factors which can affect preoperative patient anxiety such as the necessity of procedure, postoperative pain, and patient's conception of his body image. The aim of this study was to assess the relation of patients' preoperative anxiety and postoperative patients' satisfaction in dental implant surgery.
Materials and Methods:
Dental implants were placed in 40 patients (19 male and 21 female) who were referred to Dental Implant Surgery Department in Imam Reza clinic, during March–December of 2014 in Shiraz. The procedures were performed with or without bone regeneration. Preoperative anxiety was evaluated using Corah Dental Anxiety Scale, and postoperative satisfaction was determined on the basis of pain intensity, bleeding tendency, inability to eating, and overall satisfaction by filling a questionnaire in the 2nd or 3rd week after surgery. Data were collected and analyzed using Mann-Whitney test.
Results:
Preoperative anxiety was detected as high in 10%, mild in 85%, and moderate in 5% of patients. Anxiety and depression score did not differ in both genders. There was no statistical difference between neither level of anxiety nor depression in both high and low educated patients. Postoperative bleeding, difficulty in eating, and overall satisfaction was nearly the same in both genders. Statistical analysis demonstrated a lower pain level and higher pain threshold in men than women (P = 0.007). Patients' age was not related to anxiety, depression, amount of bleeding, pain, and difficulty in eating. Overall dental care satisfaction was similar in both men and women.
Conclusion:
The results of the study indicated that while anxiety does play a role in the perception of pain by patients undergoing implant surgery, overall patient satisfaction and post surgical outcomes did not significantly differ.
doi:10.4103/1735-3327.215968
PMCID: PMC5654231
Anxiety; dental; implant; stress; surgery
21.  Management of exaggerated gag reflex in dental patients using intravenous sedation with dexmedetomidine 
Dental Research Journal  2017;14(5):356-358.
Pharmacological sedation is one of the effective ways of prevention of gag reflex development in patients experiencing anxiety and fright before dental treatment. We are reporting a case where we could successfully eliminate exaggerated gag reflex (intravenous [IV] Gagging Severity Index) in a dental patient using IV sedation with dexmedetomidine. IV administration of dexmedetomidine provided elimination of gag reflex at a depth of sedation for the patient with the Richmond Agitation-Sedation Scale score of −2 and −1. The patient received dexmedetomidine 1.0 μg/kg for 10 min and then a continuous infusion of dexmedetomidine 0.4 μg/kg/h. The use of dexmedetomidine for sedation may be an alternative to other pharmacological agents in patients with dental anxiety accompanied by exaggerated gag reflex.
PMCID: PMC5654232
Dentistry; dexmedetomidine; gagging; sedation
22.  Agenesis of permanent canines: Rare case report 
Dental Research Journal  2017;14(5):359-362.
Agenesis of permanent canines is a rare condition, and that of both maxillary and mandibular permanent canines is extremely rare. It may occur either isolated or in association with other dental anomalies. Reports of such cases are very scarce in the literature. Need for early diagnosis of such conditions should be emphasized because of functional, esthetic, and psychological problems which should be evaluated and treated appropriately. The present paper presents a report of bilaterally missing permanent maxillary and mandibular canines. This case might contribute in the future studies of incidence of agenesis of permanent canines.
PMCID: PMC5654233
Agenesis; canine; incidence; permanent
23.  Analytical methods for the measurement of polymerization kinetics and stresses of dental resin-based composites: A review 
Dental Research Journal  2017;14(4):225-240.
Resin-based composites are commonly used restorative materials in dentistry. Such tooth-colored restorations can adhere to the dental tissues. One drawback is that the polymerization shrinkage and induced stresses during the curing procedure is an inherent property of resin composite materials that might impair their performance. This review focuses on the significant developments of laboratory tools in the measurement of polymerization shrinkage and stresses of dental resin-based materials during polymerization. An electronic search of publications from January 1977 to July 2016 was made using ScienceDirect, PubMed, Medline, and Google Scholar databases. The search included only English-language articles. Only studies that performed laboratory methods to evaluate the amount of the polymerization shrinkage and/or stresses of dental resin-based materials during polymerization were selected. The results indicated that various techniques have been introduced with different mechanical/physical bases. Besides, there are factors that may contribute the differences between the various methods in measuring the amount of shrinkages and stresses of resin composites. The search for an ideal and standard apparatus for measuring shrinkage stress and volumetric polymerization shrinkage of resin-based materials in dentistry is still required. Researchers and clinicians must be aware of differences between analytical methods to make proper interpretation and indications of each technique relevant to a clinical situation.
PMCID: PMC5553250  PMID: 28928776
Analytical procedure; polymerization; resin composite; shrinkage; stress
24.  Determination of salivary urea and uric acid of patients with halitosis 
Dental Research Journal  2017;14(4):241-245.
Background:
Halitosis is the presence of unpleasant or foul smelling breath. The origin of halitosis may be related to both systemic and oral conditions, but a large percentage of cases, about 90%, is generally related to an oral cause. The aim of this study was to compare the concentration of urea and uric acid in patients with halitosis and people without halitosis.
Materials and Methods:
In this case–control study, concentration of urea and uric acid was compared between two groups: (1) persons suffering halitosis (2) control group without halitosis. Each group includes fifty patients. Unstimulated saliva was collected in both groups. Then, concentration of urea, uric acid, and creatinine was determined. The results were statistically analyzed with SPSS software version 14 (SPSS Inc., Chicago, Illinois, USA) by t-test (α = 0.05).
Results:
Results showed that salivary urea and uric acid concentration in halitosis group were significantly greater than control group (P < 0.05). Salivary creatinine concentration in halitosis group was significantly lower compared to control group (P < 0.05). Salivary urea and uric acid concentration to creatinine ratios were higher in halitosis group than control group, and significant differences between them were existed (P < 0.05).
Conclusion:
According to the results, urea and uric acid concentration show increase in patient suffering halitosis, and this increase may result in oral malodor.
PMCID: PMC5553251  PMID: 28928777
Halitosis; saliva; urea; uric acid
25.  Effectiveness of Morinda citrifolia juice as an intracanal irrigant in deciduous molars: An in vivo study 
Dental Research Journal  2017;14(4):246-251.
Background:
The purpose of this study was to evaluate the microbial reduction in deciduous molars using Morinda citrifolia juice (MCJ) as irrigating solution.
Materials and Methods:
This was a randomized comparative study including 60 deciduous molars chosen among the patients belonging to the age group of 6–9 years based on the inclusion or exclusion criteria. The selected teeth were divided randomly into two groups based on irrigation solution used, that was, Group I (1% NaOCl) and Group II (MCJ). The microbial samples were collected both pre- and post-irrigation and were transferred for microbial assay. Paired t-test was used for intragroup analysis of pre- and post-operative mean reduction of bacterial colony forming unit (CFU)/ml, whereas Independent t-test was used to assess the intergroup, pre- and post-operative mean reduction of bacterial CFU/ml.
Results:
In the intragroup comparison, both of the groups showed statistically significant (P < 0.001) reduction in the mean CFU/ml; however, it did not show statistically significant reduction when intergroup comparison was carried out between the two groups. Both the study materials had clinically revealed decrease in the microbial count postirrigation.
Conclusion:
Both the irrigants, 1% NaOCl and MCJ, were significantly effective in the reduction of mean CFUs/ml postoperatively. The results of this study have confirmed the antibacterial effectiveness of MCJ in the root canals of deciduous teeth. Considering the low toxicity and antibacterial effectiveness of MCJ, it can be advocated as a root canal irrigant in endodontic treatment of primary teeth.
PMCID: PMC5553252  PMID: 28928778
Deciduous; molar; plant extracts; sodium hypochlorite

Results 1-25 (790)