Journal of dentistry (Shiraz, Iran)最新文献

Cholesterol granuloma is the result of foreign body type response to the deposition of cholesterol crystals in the tissues. It is usually associated with chronic middle ear diseases and the middle ear and mastoid antrum are the most common location for this lesion. Histopathological findings are accumulation of cholesterol clefts, ghost cells, chronic inflammatory cells, and giant cells in a fibrous granulation tissue. Cases of cholesterol granuloma have been recently reported in the jaws but still they are few in the literature of dentistry. This article presents a unique case of cholesterol granuloma occurring in the lower lip secondary to a history of trauma.

Statement of the problem: Dental caries and periodontal disease are the most common oral problems. Chemical antibacterial agents often have side effects; thus, researchers have long been in search for organic and herbal products to prevent dental caries and periodontal disease.

Purpose: The present study has aimed to assess the effects of Dracocephalum moldavica essential oil on Streptococcus mutans, Streptococcus salivarius, Streptococcus sobrinus, and Lactobacillus acidophilus compared to Chlorhexidine (CHX).

Materials and method: In this in vitro study, the plants were collected from Zanjan Province, Iran. Analysis of the essential oil was carried out by gas chromatography/mass chromatography. Micro-broth dilution and disc diffusion methods were used for assessment of the antimicrobial activity, and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were evaluated.

Results: The mean diameter of the growth inhibition zones in the well plate method for Dracocephalum moldavica showed that it had greater antimicrobial activity against Lactobacillus acidophilus than others (p Value= 0.01). Furthermore, Dracocephalum moldavica had higher antimicrobial activity than CHX. The results of MIC and MBC showed that Dracocephalum moldavica had lower antibacterial activity than CHX.

Conclusion: Dracocephalum moldavica essential oil demonstrated antibacterial properties against cariogenic bacteria. Given that other favorable properties of these essential oils are confirmed, they may be suitable for use as antibacterial agents in the formulation of oral healthcare products.

Statement of the problem: Dental caries are among the most common oral and dental diseases affecting adults and children. To prevent caries, either the factors that cause caries should be reduced or the host resistance should be increased. Several compounds, such as bioglass, chitosan, and silver diamine fluoride (SDF), can enhance enamel remineralization.

Purpose: This study was conducted to investigate the effects of chitosan, bioglass, chitosan-bioglass, and SDF compounds on remineralizing primary enamel lesions.

Materials and method: In this in vitro study, seventy-two primary canine teeth were collected. The teeth were exposed to a demineralization solution for 72 hours to create primary caries lesions. The primary Vickers microhardness test (VMT) was conducted to measure the initial values. The samples were randomly divided into six groups (n=12): Group 1: bioglass-chitosan solution; Group 2: chitosan; Group 3: bioglass solution; Group 4: SDF; Group 5: remineralization solution; Group 6: distilled water. The solutions of Groups 1, 2, and 3 were applied to the samples for 7 days, while the SDF solution was applied only once. The samples were immersed in an artificial saliva solution, which was refreshed daily. After the treatment, the final Vickers microhardness test (VMT) values were recorded. The data were analyzed statistically using a two-way ANOVA and Tukey's test (p< 0.05).

Results: The results indicated a statistically significant effect of remineralizing compounds on both pre-treatment and post-treatment microhardness (p< 0.0001). However, no significant difference in microhardness was observed between the groups studied (p= 0.225).

Conclusion: All the compounds utilized in this study demonstrated a significant remineralizing effect on enamel lesions caused by primary caries in primary teeth. The chitosan-bioglass and bioglass groups exhibited the highest levels of remineralization, respectively. However, the comparison between the groups yielded insignificant results due to the dispersion of the samples. Therefore, further studies with larger sample sizes are recommended.

Statement of the problem: Healing of the inferior alveolar nerve injury during dental procedures is one of the biggest concerns of dentists. There are still debates on different treatment modalities.

Purpose: This study aimed to compare the effect of 940nm and 810nm diode lasers on the repair of the inferior alveolar sensory nerve.

Materials and method: In this single-blinded randomized clinical trial, 39 patients with inferior alveolar nerve injury were divided into three groups: 1. 810nm laser irradiated, 2. 940nm laser irradiated, and 3. No laser irradiation (control group). All patients were treated in 12 sessions (3 days per week) and evaluated using a complete clinical neurosensory test (CNT), including brushstroke, 2-point discrimination, pinprick nociception, and thermal discrimination before and after treatment.

Results: The mean dysesthesia of the patient treated with 810nm diode laser was significantly lower than the control group in all sessions (the 1^st (p= 0.003), 3^rd (p= 0.008), 7^th (p= 0.006), and 12^th sessions (p= 0.005)). The 810nm laser resulted in more satisfaction in patients than the control group in almost all sessions (1^st (p< 0.001), 7^th (p= 0.028), and 12^th (p= 0.006)). More patient satisfaction was seen in the 1^st and 3^rd sessions in the 810nm laser than in the 980nm laser (p< 0.001 and p= 0.003, respectively).

Conclusion: 810nm diode laser can be better than 940nm in repairing inferior alveolar sensory nerve damage.

Statement of the problem: During endodontic therapy, irrigation solutions applied in the root canal may affect the physicochemical properties of the dentinal wall, thereby changing its microhardness. This may adversely affect the sealing ability and adhesion of dental materials. Therefore, many studies have focused on the search for an ideal root canal irrigant that has a minimal effect on dentinal microhardness.

Purpose: This in vitro study was conducted to determine the changes in dentin microhardness after root canal irrigation with different endodontic irrigants.

Materials and method: Ninety-five freshly extracted maxillary central incisor teeth with straight single canals were selected. These teeth were sectioned transversely at the level of the cementoenamel junction. The working length of each tooth was determined, and canal space was prepared by the HyFlex CM rotary file system. During instrumentation, normal saline was used for irrigation. Then, teeth were split longitudinally into two segments. According to the irrigating solution employed, samples were divided into five groups (n=19): normal saline (Group A), 3% sodium hypochlorite (Group B), 2% chlorhexidine (Group C), 5% calcium hypochlorite (Group D), and 0.2% nanochitosan (Group E).3 mL of the corresponding irrigating solution was administered for total15 minutes in each prepared sample. The Vickers micro-hardness tester was then used to assess micro-hardness. The data was analyzed using one-way analysis of variance (ANOVA).

Results: All tested irrigating solutions decreased the dentinal microhardness. Samples irrigated with 5% calcium hypochlorite demonstrated dentinal microhardness of 42.43±1.62, which is the lowest among all the tested groups, followed by nano chitosan, sodium hypochlorite, and chlorhexidine. Samples treated with control group (saline) demonstrated the maximum microhardness of dentin in the present study.

Conclusion: Within the limitations of this research, it can be concluded that the tested novel irrigating solutions, 5% calcium hypochlorite and 0.2% nanochitosan, were more detrimental to radicular dentin microhardness when compared with conventional endodontic irrigants.

Statement of the problem: Conventional injection technique with adrenaline during removal of impacted third molar of mandible had proportionally increased pain during administration with slow onset of action and shorter duration of anesthesia.

Purpose: The purpose of this study was to compare the effective nature of 8.4% and 7.5% buffered lidocaine hydrochloride during surgical removal of mandibular impacted third molar.

Materials and method: This prospective crossover study included 50 patients requiring bilateral removal of impacted mandibular third molars. Group I included 50 impacted mandibular third molars that were administered with 8.4% buffered lidocaine hydrochloride and group II included 50 impacted mandibular third molars were administered with 7.5% buffered lidocaine hydrochloride. The outcome variables were pain on injection, time of onset of anesthesia, and duration of action of anesthesia. The above parameters were recorded by the investigator and statistically analyzed through Chi-square test using SPSS software.

Results: Patients in group I had mild pain (1.02) and patients in group II (5.74) had moderate pain with a statistical significance of p< 0.05 for group I respectively. The mean onset of action of anesthesia in group I was 0.08 seconds and 0.59 seconds in group II (p< 0.05). The duration of anesthesia was 342.51 minutes from group I and 122.06 minutes in group II (p< 0.05) respectively.

Conclusion: Lidocaine hydrochloride buffered with 8.4 % sodium bicarbonate was found to be more effective in reduction of pain during injection, also had a faster onset of action and longer duration of the action of anesthesia when compared to 7.5% buffered lidocaine hydrochloride.

Statement of the problem: Paxillin (PXN) is one of the proteins involved in cell adhesion. PXN and integrins constitute a key site for the focal adhesion between the cell and extracellular matrix. Several studies have shown that PXN is a factor in tumor formation, progression, invasion, and metastasis.

Purpose: This study evaluated PXN expression in four types of odontogenic lesions with different aggressive behaviors.

Materials and method: In this retrospective cross-sectional study, PXN expression was immunohistochemically assessed in 68 paraffin-embedded tissue samples from patients with the confirmed diagnosis of four types of odontogenic lesions, including 14 dentigerous cysts (DC), 20 odontogenic keratocyst (OKC), 16 unicystic ameloblastoma, and 18 solid ameloblastoma. The PXN expression in these samples were scored based on the percentage and intensity of immunoreactivity, and compared among the groups by Chi-square test.

Results: The PXN marker was detected in the cytoplasm of tumor cells (unicystic and solid ameloblastoma) and the epithelial layer of cysts (DC and OKC). The intensively stained marker of PXN was observed in 9 cases (64.3%) of the DC, 14 cases (70%) of OKC, 12 cases (75%) of unicystic ameloblastoma, and 13 cases (72.2%) of solid ameloblastoma. However, there was not statistical difference of PXN protein expression between DC and OKC (p Value = 0.51) and unicystic and solid ameloblastoma (p = 0.58), also the same was true for cysts and tumors (p = 0.37).

Conclusion: The expression of PXN is not related to the biological behaviors of odontogenic lesions.

Statement of the problem: Although various kinds of research have been conducted to compare the physical and chemical properties of dentin and enamel in animal and human samples, proving the ability of animal dentin material as a good substitute for human specimens is always a challenge for experimental studies.

Purpose: The aim of the present study is to investigate whether the changes in the dentin microhardness of animal samples are similar to those of human samples or not.

Materials and method: In this in vitro study, sixty single-rooted human, bovine, and ovine teeth (n=20 in each group) were decoronated at CEJ. The remaining roots were embedded in acrylic resin and a cross-section cut was made in the middle of the samples in order to achieve dentin disks. All of the 120 samples were randomly assigned to three control (n=20 for each group) and three experimental groups (n=20 for each group). In the experimental groups, calcium hydroxide with a creamy consistency was prepared and the disks were embedded in dishes containing calcium hydroxide. Control groups were embedded in physiological saline. The samples were incubated for seven days at the 37oC and Vickers microhardness test was performed immediately. The average of three yielded values was considered as the final value of microhardness. Data were analyzed using two-way ANOVA, one-way ANOVA, and Tukey's post hoc tests.

Results: In the control group, the human samples showed the highest microhardness value, while the bovine teeth had the lowest microhardness value (p< 0.001). In the calcium hydroxide group, the human samples showed the highest microhardness value in comparison to bovine and ovine to teeth. However, no significant difference was observed between the bovine and ovine samples in microhardness value.

Conclusion: Based on our research, substituting bovine and ovine samples with human samples in experimental studies is not recommended. Nevertheless, more studies are needed in this regard.

Statment of the problem: Podoplanin can indicate the lymphangiogenesis. On the other hand, lymphangiogenesis affects the biological behavior of lesions. The clinical behavior of odontogenic keratocysts (OKC) and dentigerous cysts (DC) is different.

Purpose: This study aimed to evaluate the immunohistochemical expression of podoplanin and to investigate lymphangiogenesis in OKCs as compared to DCs.

Materials and method: In this experimental laboratory study, sixty paraffined blocks, including 30 OKC and 30 DC samples, were examined in this study, all of which were histopathologically non-inflamed. To evaluate lymphangiogenesis, the immunohistochemical reaction of D2-40 was evaluated via cytoplasmic and membrane staining of lymphatic endothelial cells. The expression of podoplanin in the epithelial cells of two cyst groups was also examined. To analyze the collected data and compare the results between the two groups of cysts, independent samples t-test, Mann-Whitney U test, and Chi-square test were performed in SPSS version 22. The significance level was set at 0.05.

Results: The mean lymph node count and podoplanin expression were significantly higher in the OKC epithelium as compared to DC (p< 0.001). Based on the results, 90% of OKC samples and 43.3% of DC samples showed grade 3 staining.

Conclusion: The rate of lymphangiogenesis and podoplanin expression in the epithelium were higher in OKCs compared to DCs. According to the results, the expression of podoplanin may be a useful marker for determining the invasiveness and proliferation of OKC.

Statement of the problem: Successful endodontic treatment depends on three-dimensional (3D) root canal filling to prevent the leakage of residual bacteria. Different obturation techniques with different sealers should be compared by employing advanced assessment tools.

Purpose: This study compared the obturation quality of warm vertical compaction (WVC) and two different single-cone (SC) techniques using micro-computed tomography (micro-CT).

Materials and method: Thirty-three extracted maxillary molars with mesial root canal curvature of 20‒40º were prepared in vitro with One-Curve files and randomly assigned to three groups (n=11) for root canal obturation with WVC, SC technique with AH Plus sealer (SC-AH), or SC technique with SureSeal bioceramic (BC) sealer (SC-Su). The root canals underwent micro-CT examinations before and after obturation to determine the volume percentages (VPs) of voids and gaps at different distances from the apex (coronal, middle, and apical thirds). Data were analyzed by Kruskal-Wallis and Mann-Whitney U tests.

Results: The highest VP of voids and gaps was recorded in the SC-Su group, with no significant difference from other groups (p> 0.05). There were significant differences in VP of gaps at different distances from the apex (p<0.05). The VPs of gaps in the apical third of all the samples were significantly higher than in the coronal and middle thirds. However, the difference in VP of voids was not significant at different distances from the apex (p>0.05).

Conclusion: None of the tested techniques could provide a void-free and gap-free filling. The apical third of the canals showed the highest VP of gaps in all obturation techniques.