سال:1399 | دوره: | شماره: |تعداد مقالات:9

Background. Orthodontic tooth movement (OTM) occurs in the alveolar bone; therefore, any condition affecting bone quality can alter OTM. This study aimed to evaluate the effect of amitriptyline on OTM in rats. Methods. Forty-five male Wistar rats were randomly divided into three groups: (I) no injection, (II) injection with saline solution, and (III) injection of amitriptyline. Next, a-60gr force was applied to the maxillary left first molar tooth of all the rats, using a nickel‒ titanium closed-coil spring ligated between the maxillary incisors and the left first molar tooth. The rats were sacrificed after 21 days to measure OTM and perform histological analysis to determine the number, width, and depth of resorptive lacunae, osteoclast counts, and periodontal ligament (PDL) width. Results. The highest and the lowest OTM rates were found in the control and amitriptyline groups, respectively; however, there was no significant difference between the study groups in this regard. Histological analysis showed a significantly lower number of resorption lacunae in the amitriptyline group than the saline group. Conclusion. Although no significant difference was noted in OTM after amitriptyline administration, a reduction in the number of resorptive lacunae in rats injected with amitriptyline suggests that amitriptyline affects the bone tissue at the cellular level.

Background. The present study aimed to evaluate the impact of continuous irrigation with saline solution at room temperature or ° 4+C on the cyclic fatigue resistance of K3XF files. Methods. Forty-eight new K3XF files (04., 30# taper) were randomly assigned to three groups: control group (no irrigation), continuous irrigation with saline solution at room temperature, and continuous irrigation with saline solution at ° 4+C. The instruments were tested in an artificial, stainless steel root canal with a double curvature at body temperature (° 1± 37C). Time to fracture was converted to the number of cycles to fracture (NCF). The lengths of the fractured fragments were recorded. Kruskal– Wallis H test and one-way ANOVA were used to analyze data. Results. K3XF files’ cyclic fatigue resistance was significantly higher in the continuous irrigation groups than in the control group. Continuous irrigation with saline solution at ° 4+C resulted in higher cyclic fatigue resistance than continuous irrigation with saline solution at room temperature. There were no significant differences between the groups in terms of the fractured fragments’ length. Conclusion. Within this study’ s limitations, continuous irrigation with saline solution increased the NCF of NiTi instruments; decreasing the saline solution’ s temperature increased this effect.

Background. Dental plaster, white orthodontic gypsum, and construction gypsum have β-hemihydrate particles. Setting time is an essential property of dental gypsum, which can affect the strength of the material. This research aimed to compare construction gypsum, dental plaster, and white orthodontic gypsum’ s initial and final setting times. Methods. Three groups were included in this experimental laboratory study: construction gypsum (A), dental plaster (B), and white orthodontic gypsum (C). Each group consisted of 10 samples. Gypsum manipulation consisted of using 120 gr of powder and 60 mL of water. Gypsum powder and water were mixed using a gypsum mixer at 120 rpm. A homogeneous mixture was poured into a mold, and the setting time was measured using a Gillmore needle, according to ASTM C03-266. The initial setting time test was measured using 113. 4 grams and a-2. 12mm needle. The final setting time was measured using 453. 6 grams and a-1. 06mm needle. This test was repeated until the needle failed to penetrate the gypsum’ s surface. All the data were analyzed with one-way ANOVA and post hoc Tukey tests using SPSS 23. Results. The average initial setting time for groups A, B, and C were 1. 40± 16. 17, 1. 19± 10. 39, and 1. 51± 24. 46, respectively. The average final setting time for groups A, B, and C were, 0. 79± 15. 97 0. 88± 24. 31) and 0. 66± 33. 37, respectively. One-way ANOVA and post hoc Tukey tests showed significant differences in the initial and final setting times between the three groups (P<0. 05). Conclusion. There were differences in setting time between dental plaster, white orthodontic gypsum, and construction gypsum. The construction gypsum’ s setting time is suitable as a type II dental gypsum, according to ADA No. 25.

Background. Corrosion resistance and ion release of alloys play a crucial role in biomedical applications. The present study aimed to investigate an increase in corrosion resistance and reduction in ion release in a commercial Co-Cr-Mo alloy by the chemical passivation method. Methods. Based on ADA20, 97 samples of Flexicast alloy were cast, surface-polished, and electrolytically passivated at room temperature for 24 h in a sodium sulfate solution. Corrosion and ion release of the alloys before and after passivation were studied in normal saline solution. Corrosion resistance and the ion release rates were measured by the weight loss method and atomic absorption spectroscopy, respectively, before and after passivation after 3, 2, 1, and 4 weeks. The surface morphology of the samples was examined using scanning electron microscopy (SEM). The results were analyzed with Kruskal-Wallis and Mann-Whitney tests using SPSS 20 at a significance level of <0. 05. Results. The corrosion rate in the passivated samples was significantly lower than the non-passivated samples at the intervals (3, 2, 1, and 4 weeks) (P<0. 05). The passivation of the alloy significantly reduced Co and Cr ion release in the first and fourth weeks, and in the first, second, and fourth weeks, respectively (P<0. 05). SEM images revealed localized pitting associated with the corrosion, which was less significant in passivated samples. Conclusion. Chemical passivation of the CR-Co alloy significantly reduced corrosion and ionic release of Cr and Co over time.

Background. This study aimed to compare the VDW. ROTATE instruments with the Reciproc Blue instruments in different kinematics in terms of the cyclic fatigue resistance. Methods. Sixty instruments, 40 VDW. ROTATE and 20 Reciproc Blue instruments, were divided into three groups (n=20): VDW. ROTATE was used in both continuous rotation and reciprocation, and Reciproc Blue was used in reciprocation only. The cyclic fatigue resistance test was carried out in an artificial canal (° 60, r=3 mm) at an intracanal temperature of ° 2± 35C until fracture, and the time to fracture was recorded in seconds. The data were analyzed statistically using Kruskal– Wallis and Tamhane’ s T2 tests (P<0. 05). Results. DAll the reciprocating motion groups resulted in a longer mean duration to failure than the continuous rotation motion group (P<0. 05). Conclusion. It was observed that the Reciproc Blue instruments had higher cyclic fatigue resistance than VDW. ROTATE instruments (P<0. 05). Recent studies have shown that reciprocal movement increases cyclic fatigue resistance compared to rotational movement. The VDW. ROTATE instrument, which has a similar size, design, and alloy as the Reciproc Blue instrument, can also be used by clinicians in reciprocating motion with endo motors capable of reciprocating in different directions. However, even if the cyclic fatigue resistance increases by using VDW. ROTATE instruments in reciprocation, the cyclic fatigue resistance is lower than Reciproc Blue instruments.

Background. One of the essential properties of sealers used during endodontic treatment is their biocompatibility. Different materials are added to these sealers to improve their properties, including antibacterial activity. In recent years, there has been an increase in interest in the use of herbal medicines. This study aimed to evaluate the effect of incorporating triphala into AH26 sealer on its cytotoxicity on gingival fibroblasts at different intervals after mixing. Methods. In the present in vitro study, the cytotoxicity of AH26 sealer was evaluated once in its pure form and once after mixing it with triphala at-48,-24, and-72hour, and-7day intervals after mixing using the standard MTT assay protocol on gingival fibroblasts. Results. Two-way ANOVA was used to evaluate the effect of groups on the mean changes in cytotoxicity at different time intervals at a significance level of P<0. 05. The results showed that the incorporation of triphala into the AH26 sealer did not increase or decrease its cytotoxicity (P=0. 909). Besides, there was a decrease in cytotoxicity in both study groups. However, there was a relative increase in the sealers’ cytotoxicity in both groups in the first 72 hours (P<0. 0001). Conclusion. Considering the well-established antibacterial properties of triphala in our previous study, the present study’ s results showed that the incorporation of triphala into the AH26 sealer did not increase the cytotoxicity of the sealer. Therefore, it can be incorporated into the AH26 sealer to improve the other properties of the sealer, including its antibacterial activity.

Background. This study purposed to compare the effect of new single glide path files on extruded apical debris and total preparation times during root canal preparation with the WaveOne Gold system. Methods. Thirty-six extracted human lower molar teeth with mesiobuccal canal curvature angles of ° 35‒ 25 were randomly splited to three groups. In group 1, the glide path was created with WaveOne Gold Glider (WGG) file at working length (WL); in group 2, the glide path was created with ProGlider file (PG); in group 3, the glide path was not performed. In all the groups, the root canals were shaped with WaveOne Gold Primary (WOG) reciprocating files at WL. Apically extruded debris during instrumentation was picked up into pre-weighed Eppendorf tubes. The weight of the dry extruded debris was calculated by subtracting the pre-and post-instrumentation weights of the tubes in each group. The total time elapsed during the canal preparation was calculated with a chronometer. The data were analyzed using one-way ANOVA and post hoc Tukey tests. Results. The WGG/WOG group extruded significantly fewer debris than the WOG and PG/WOG groups (P<0. 05). There was no significant difference between the WOG and PG/WOG groups (P>0. 05). The WGG/WOG and PG/WOG groups were significantly faster than the WOG group. Conclusion. The amount of debris extruded apically significantly diminished when conventional WGG was implemented before using WOG. The total preparation time significantly diminished when the WOG file was used in combination with reciprocating and rotary glide path preparation techniques.

Background. Conventional mechanical debridement alone cannot eliminate bacteria and their products from periodontal pockets. Adjunctive therapies improve tissue healing through detoxification and bactericidal effects. Photodynamic therapy (PDT) is a non-invasive treatment procedure that involves the use of a dye as a photosensitizer to attach to the target cell and be activated by a photon of an appropriate wavelength. This study aimed to assess the effectiveness of PDT in treating periodontitis as an adjunct to scaling and root planing. Methods. Fifteen subjects with chronic periodontitis were treated randomly with scaling and root planing (SRP), followed by a single PDT (test) or SRP (control) episode alone. Full-mouth plaque index (PI), sulcus bleeding index (SBI), probing depth (PD), and clinical attachment level (CAL) were assessed at baseline and-1month and-3month intervals. Microbiological evaluation of Porphyromonas gingivalis (Pg) in subgingival plaque samples was performed using a commercially available real-time polymerase chain reaction. Results. The results revealed a significant difference in PI, SBI, PD, CAL, and microbiological parameters between the groups one and three months after treatment. Conclusion. A combination of PDT and SRP gave rise to a significant improvement in clinical and microbiological parameters in patients with chronic periodontitis.

Background. This study investigated the effect of non-surgical periodontal treatment on clinical indices and salivary levels of visfatin, chemerin, and progranulin in diabetic patients with periodontitis. Methods. This interventional clinical trial was performed on 20 patients with type II diabetes mellitus (T2DM) with moderate to severe chronic periodontitis (periodontitis stages II or III according to the new classification of periodontal diseases). Clinical indices, including gingival index (GI), probing pocket depth (PPD), clinical attachment level (CAL) and plaque index (PI), were recorded and visfatin, chemerin, and progranulin adipokines levels were also measured in unstimulated saliva by ELISA technique at baseline and twelve weeks after non-surgical periodontal treatment. Results. GI dropped from 0. 27± 1. 92 to 0. 14± 0. 71 after the intervention (P<0. 001). Also, there were significant changes in the PPD and PI (P<0. 001). However, no significant changes were observed in the CAL (P<0. 05). The concentrations of all three salivary adipokines decreased after treatment, but this change was statistically significant only for progranulin (P<0. 05). Conclusion. Non-surgical periodontal therapy resulted in improvements in the clinical indices of GI, PPD, and PI in T2DM patients with periodontitis. Moreover, the significant reduction in the salivary level of progranulin after treatment suggests that it might be considered a target inflammatory marker in periodontal diseases.