Investigation of mechanical properties, remineralization, antibacterial effect, and cellular toxicity of composite orthodontic adhesive combined with silver-containing nanostructured bioactive glass.

BACKGROUND: The formation of white spots, which represent early carious lesions, is a major issue with fixed orthodontics. The addition of remineralizing agents to orthodontic adhesives may prevent the formation of white spots. The aim of this study was to produce a composite orthodontic adhesive combined with nano-bioactive glass-silver (nBG@Ag) for bracket bonding to enamel and to investigate its cytotoxicity, antimicrobial activity, remineralization capability, and bond strength. METHODS: nBG@Ag was synthesized using the sol-gel method, and characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy with an attenuated total reflectance attachment (ATR-FTIR). The cytotoxicity test (MTT) and antimicrobial activity of adhesives containing 1%, 3%, and 5% (wt/wt) nBG@Ag were evaluated, and the shear bond strength of the adhesives was measured using a universal testing machine. Remineralization was assessed through microhardness testing with a Vickers microhardness tester and scanning electron microscopy (SEM). Statistical analyses were conducted using the Shapiro-Wilk test, Levene test, one-way ANOVA, Robust-Welch test, Tukey HSD method, and two-way ANOVA. RESULTS: The biocompatibility of the adhesives was found to be high, as confirmed by the lack of significant differences in the cytotoxicity between the sample and control groups. Discs made from composites containing nBG@Ag exhibited a significant reduction in the growth of Streptococcus mutans (p < 0.05), and the antibacterial activity increased with higher percentages of nBG@Ag. The shear bond strength of the adhesives decreased significantly (p < 0.001) after the addition of nanoparticles, but it remained above the recommended value. The addition of nBG@Ag showed improvement in the microhardness of the teeth, although the differences in microhardness between the study groups were not statistically significant. The formation of hydroxyapatite deposits on the tooth surface was confirmed through SEM and energy-dispersive X-ray spectroscopy (EDX). CONCLUSION: Adding nBG@Ag to orthodontic adhesives can be an effective approach to enhance antimicrobial activity and reduce enamel demineralization around the orthodontic brackets, without compromising biocompatibility and bond strength.

Evaluation of shear bond strength and enamel remineralizing effect of experimental orthodontic composite containing nano-hydroxyapatite: An in vitro study.

OBJECTIVE: The purpose of this study was to prepare an orthodontic composite containing hydroxyapatite nanoparticles to prevent demineralization and create a suitable environment for mineral deposition around orthodontic brackets, and to investigate the mechanical and remineralizing properties of the experimental adhesive composite. METHODS: Experimental orthodontic composite were formulated using varying percentages of nano-hydroxyapatite particles. Assessments were based on four groups: a control group (3M™ Transbond™ XT) and experimental composites containing 2% (HA2), 5% (HA5) and 10% (HA10) hydroxyapatite. Vickers Microhardness test was performed to investigate the remineralizing effect in 3 stages: initial stage, after demineralization and after 4 weeks of exposure to artificial saliva. Scanning electron microscopy with energy dispersive X-ray spectroscopy analyser (SEM/EDAX) was used to evaluate hydroxyapatite precipitation and elemental composition of enamel surface. Shear Bond Strength tests were carried out using a universal testing machine and the debonding pattern was assessed using Adhesive Remnant Index (ARI). RESULTS: All groups showed clinically acceptable SBS values. The highest SBS was achieved in the HA2 group, followed by Transbond™ XT, HA5 and HA10. There was no significant difference in the ARI scores. In terms of microhardness properties, HA5 and HA10 demonstrated a significant increase after 4 weeks. The results of SEM analysis showed the precipitation of hydroxyapatite crystals and EDAX analysis indicated the increase of calcium and phosphate ion peaks compared to the demineralized sample. The data were analysed using one-way ANOVA and Tukey's Post-hoc test. CONCLUSIONS: Addition of hydroxyapatite nanoparticles to orthodontic composite can increase the mineral content and microhardness of the adjacent enamel. However, increasing the amount of nanoparticles reduces shear bond strength in a decreasing trend. The above-mentioned findings showed that incremental increase of nanoparticles of HA can be incorporated in composite to a certain extent and limitations are determined by mechanical properties (SBS) required for bracket bonding.

Comparative study of changes in the airway dimensions following the treatment of Class II malocclusion patients with the twin-block and Seifi appliances.

BACKGROUND: Functional appliances are frequently used to stimulate mandibular growth in cases of Class II malocclusion with mandibular deficiency. Many studies have reported improved pharyngeal airway passage (PAP) dimensions following functional appliance therapy in children. OBJECTIVES: The present study aimed to assess changes in the airway dimensions following the treatment of Class II malocclusion patients with the twin-block and Seifi appliances. MATERIAL AND METHODS: Lateral cephalograms of 37 patients with Class II malocclusion and mandibular deficiency treated with the twin-block appliance (n = 20) or the Seifi appliance (n = 17) were assessed in this before-and-after study. The preoperative and postoperative lateral cephalograms were compared to determine changes in the airway dimensions at the level of the palatal plane (PP), the occlusal plane (OP) and the 2nd-4th cervical vertebrae (C2-C4) in the 2 groups. The results were analyzed with the t test and the one-way analysis of covariance (ANCOVA). RESULTS: After treatment, significant changes occurred in the point A-nasion-point B (ANB) and sellanasion-point B (SNB) skeletal cephalometric indices in the twin-block appliance group, and in ANB, SNB and incisor-mandibular plane angle (IMPA) in the Seifi appliance group. The airway dimensions at the level of PP, OP and the 3rd cervical vertebra (C3) significantly increased postoperatively as compared to the baseline in the twin-block appliance group (p < 0.05). The increases in the airway dimensions at the level of PP and C3 in the twin-block appliance group were significantly greater than in the Seifi appliance group (p < 0.05). CONCLUSIONS: The treatment of Class II Division I malocclusion with the twin-block appliance significantly increased the airway dimensions at the level of PP, OP and C3, whereas the Seifi appliance did not cause any significant changes in the airway dimensions.

Comparative assessment of the sealing ability of Nd:YAG laser versus a new desensitizing agent in human dentinal tubules: a pilot study.

Dentinal hypersensitivity is a painful condition that occurs following periodontal treatment. Many treatment alternatives have been considered for this problem, including treatments with laser and dentinal adhesives. This study compared the sealing ability of Nd:YAG laser versus a new resin in scanning electron microscopy (SEM) micrographs. Ten human premolars were sectioned yielding 30 specimens of each premolar, which were randomly divided into three groups. The laser group was irradiated by Nd:YAG laser (1 W, 10 Hz, 60 s), the resin group was treated with the new Seal & Protect resin according to the manufacturer's instructions, and the third group served as the control group and did not receive any interventions. After preparation and gold coating of the samples, they were photographed by SEM at two magnifications (1500× and 4000×). The number and diameter (µm) of the dentinal tubules were recorded in selected fields, and analysis of variance (ANOVA) and Tukey tests were used to determine significant differences between groups. The ANOVA results revealed significant differences in both the mean number (P < 0.001) and diameter (P < 0.05) among the three groups. Further statistical analysis showed a significant difference between the laser group and the resin group in both outcome measures (P < 0.05). Thus, both Nd:YAG laser and the new resin reduced the number and diameter of open dentinal tubules, a result that also explains the desensitization mechanism of these interventions. We further conclude that application of the new resin is more effective than Nd:YAG laser in minimizing the number and diameter of exposed dentinal tubules.

Comparison of the failure rate, bonding time and ARI score of two orthodontic bonding systems: Self-Etch Primer and Conventional Etching Primer: A systematic review and meta-analysis.

OBJECTIVE: This study aimed to evaluate the failure incidence of brackets with at least six months follow-up between self-etch primer and conventional etch/primer, as well as to investigate the clinical duration of the bonding process and the amount of adhesive remnant index (ARI). METHODS: Electronic search was conducted in databases including PubMed, Scopus, Web of Science, ProQuest, ClinicalTrials.gov, and ICTRP (International Clinical Trials Registry Platform). The electronic search targeted only randomized clinical trials and was limited from January 2000 to June 2021. Delphi list is used to evaluate the risk of bias and Stata Version14.2 software was used. This systematic review was conducted according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) and recorded on the Ethics Committee of Research Institute of Dental Sciences, SBMU (IR.SBMU.DRC.REC.1398.240). RESULTS: Out of 2288 extracted studies, 30 of them entered the full-text evaluation process. According to the inclusion criteria, 15 studies entered this systematic review. Containing 607 participants and 10,563 brackets/teeth. All the included studies were of randomized clinical trials (RCT) design with either parallel or split-mouth design. Comparing the two groups, the risk difference effect (RD)=0.007 CI 95% (-0.004,0.018) indicated a neglectable difference in the risk of bracket failure during treatment between the two groups. The index I2=53.9% indicated moderate heterogeneity in the results. Furthermore, the P-value=0.007 indicated statistical insignificance between the two interventions in terms of failure rate. The clinical duration of bonding time analysis were equal to SMD _Cohen=-2.67 CI95% (-3.49, -1.85), which indicated a statistically significant reduction in clinical process time, using the self-etch primer. Data synthesis for adhesive remnant index could not be conducted due to heterogeneity among included studies. CONCLUSIONS: There was no difference between the self-etch primer and conventional etch/primer in bracket debonding at a medium level of evidence, However, there was statistically significant reduction in clinical bonding time using self-etch primer.

Evaluation of caries risk reduction following preventive programs in orthodontic patients, using Cariogram computer model: A quasi-experimental trial.

OBJECTIVE: This study evaluated the effectiveness of preventive strategies on caries risk reduction in patients undergoing orthodontic treatment, using the Cariogram program. METHODS: In this quasi-experimental study, samples were selected using a convenience quota sampling technique, in a public dental school. At first, caries risk profile was determined for each subject using the Cariogram before brackets bonding. The sample size consisted of 36 patients. The intervention group (n = 18) received preventive programs, and the control group (n = 18) was trained based on the routine oral health education by means of pamphlets. Then, Cariogram parameters were calculated for patients in both groups after six months. RESULTS: The age range of participants was from 12 to 29 years. The mean percentage of the "Actual chance of avoiding new cavities" section in the intervention group increased from 45.72 ± 21.64 to 62.50 ± 17.64. However, the mean percentage of other parameters - such as "Diet", "Bacteria" and "Susceptibility" - decreased after six months (p< 0.001). Besides, the differences in the mean percentage between intervention and control group at the end of the study period (T1) related to the Cariogram parameters were statistically significant (p< 0.001). Accordingly, the mean percentage of 'Actual chance of avoiding new cavities'' parameter in the intervention group (62.50) was statistically higher than in the control group (42.44) (p< 0.001). CONCLUSION: Implementing different preventive approaches is able to reduce the caries risk in patients undergoing fixed orthodontic treatment, which can be clearly demonstrated using Cariogram program.

The effect of 904 nm low level laser on condylar growth in rats.

A growth center of the mandible that contributes to its length and height is the mandibular condyle. Proliferation of prechondroblasts, followed by synthesis of the extracellular matrix and hypertrophy of the cartilage cells, governs the major part of condylar growth. The sample consisted of 54 male rats, weighing between 60 g and 80 g, divided randomly into three groups. Group I was the control group, group II was irradiated bilaterally, and group III was irradiated on the right side. Laser irradiation (lambda = 904 nm, 2000 Hz, pulse length 200 ns and output power 4 mW) was performed, and the procedure was repeated after a 50-day interval. Two months later, the rats were killed. In a single blind manner the lengths of denuded mandibles and the lengths of mandibles on soft tissue were measured. The growth of the mandibles in the unilaterally irradiated group (P < 0.001) and the bilaterally irradiated group (P < 0.05) was significantly more than that in the control group. There was no significant difference between right and left condylar growth in the bilaterally irradiated group (P = 0.3). Soft tissue analysis also verified these results (P < 0.001). Histomorphometric results also revealed a significant difference between laser-irradiated groups and the control group (P < 0.01). We concluded that particular laser irradiation with the chosen parameters can stimulate condylar growth and subsequently cause mandibular advancement. These findings might be clinically relevant, indicating that low level laser irradiation can be used for further improvement of mandibular retrognathism.

Strength of attachment between band and glass ionomer cement.

AIM: To determine the strength of attachment between plain stainless steel band material and glass ionomer cement. METHODS: Seventy-five extracted upper premolars, free of visible structural defects, were used. The teeth were divided randomly into three groups and embedded in acrylic resin blocks. A short length of plain, stainless steel band material with a welded stainless steel standard edgewise 0.022 inch bracket was adapted to the buccal surface of each tooth. The bracket-stainless steel pads were then cemented to the teeth with either Bandtite (Group 1), Granitec (Group 2) or Ariadent (Group 3) glass ionomer cement and stored in an incubator at 37 degrees C for 30 days. The shear bond strengths of the specimens were measured and compared. RESULTS: The mean shear bond strengths (SBS) were significantly different: Bandtite 0.7331 +/- 0.056 Mpa; Granitec 0.3869 +/- 0.047 Mpa; Ariadent 0.2931 +/- 0.033 Mpa (ANOVA, p < 0.001). Tukey HSD post-hoc tests also showed significant differences between Bandtite and Granitec, Bandtite and Ariadent, and Granitec and Ariadent (p < 0.001). All specimens failed at the band-cement interface. CONCLUSION: The highest and lowest SBS were related to Bandtite and Ariadent cements, respectively. All cements had bond strengths less than the range of bond strengths considered to be clinically acceptable for bonded orthodontic attachments. Mechanical factors are important for band retention.

Association between Lateral Cephalometric Changes in X-Y Coordinate System and Profile Changes among Skeletal Class III Patients after Orthognathic Surgery.

BACKGROUND: Since aesthetic issues are the most important causes of referring skeletal class III patients to surgeons, investigating the impact of orthognathic surgeries on improving patient profiles increases the quality of treatment and quality of life. METHODS: In a retrospective observational-analytical study, 25 patients older than 18 years with class III skeletal malocclusion who had gone under both orthodontic and double-jaw orthognathic treatment were enrolled. Cephalometric imaging interval was before and at least 6 months after surgery. By defining a number of points and coordinate axes (X-Y), a criterion for comparing hard and soft tissue changes was obtained. These measurements were coordinated, linear and angular. The quantitative data were compared with data obtained using the Likert Scale Questionnaire by means of electronic "Google Forms" that was completed by orthodontists (n=5) and maxillofacial surgeons (n=5) to rank improvement in post-surgical profiles for both cephalometry and photography from poor to pleasant. Spearman Correlation Analysis was conducted between the quantitative and qualitative data. RESULTS: Vertical changes of point B and horizontal changes of point PNS showed correlation with improvement of patient profile. Changes in N-Pog line (R=-0.4), mandibular plane angle (R=-0.4) and nasolabial angle (NLA) (R=0.38) were significantly correlated with improvement of profiles. CONCLUSION: In orthognathic double-jaw surgery on patients with skeletal Class III, forward movement of maxilla, upward positioning of mandible (decreasing anterior facial height), decreasing mandibular plane angle and increasing nasolabial angle would result in a better profile.

Innovative evaluation of local injective gel of curcumin on the orthodontic tooth movement in rats.

BACKGROUND: Curcumin is the most active compound in turmeric. It can suppress the nuclear factor kappa-light-chain-enhancer of activated B cells pathway and prevent the osteoclastogenesis procedure. This study aimed to be the first to evaluate the effect of curcumin on the rate of orthodontic tooth movement (OTM). MATERIALS AND METHODS: Forty rats were used as follows in each group: (1) negative control: Did not receive any appliance or injection; (2) positive control: received 0.03 cc normal saline and appliance; (3) gelatin plus curcumin (G): Received 0.03 cc hydrogel and appliance; and (4) chitosan plus curcumin (Ch): Received 0.03 cc hydrogel and appliance. They were anesthetized and closed nickel-titanium coil springs were installed between the first molars and central incisors unilaterally as the orthodontic appliance. After 21 days, the rats were decapitated, and the distance between the first and second molars was measured by a leaf gauge. Howship's lacunae, blood vessels, osteoclast-like cells, and root resorption lacunae were evaluated in the histological analysis. Data were analyzed by one-way ANOVA, Tukey's test, and t-test (P < 0.05 consider significant). RESULTS: No significant difference was found in OTM between groups delivered orthodontic forces. Curcumin inhibited root and bone resorption, osteoclastic recruitment, and angiogenesis significantly. CONCLUSION: Curcumin had no significant inhibitory effect on OTM. While it had a significant role on decreasing bone or root resorption (P > 0.05).

Dentoskeletal Stability in Conventional Orthognathic Surgery, Presurgical Orthodontic Treatment and Surgery-First Approach in Class-III Patients.

For many years, the conventional approach to orthognathic surgery which was orthodontic treatment prior to orthognathic surgery has been the accepted method of treatment for skeletal class III malocclusion patients. This review compared the dentoskeletal stability of treatment results between conventional orthognathic surgery methods with presurgical orthodontic treatment and surgery-first approach in skeletal class III patients. The study protocol was based on Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement for systematic review and meta-analysis. Electronic and manual searches for literature since 2011 were conducted. PubMed and Medline databases were accessed. Data extraction and analysis were performed by two independent individuals. Seven studies out of hundred-fourteen articles met the inclusion criteria and were selected for qualitative analysis. The included studies were 494 patients with skeletal class-III malocclusion. Stability of treatment was compared between surgery-first approach and conventionally treated patients. The statistical analysis confirmed that surgery-first approach did not show more stability compared with presurgical orthodontics. The surgery-first approach shortened the overall treatment duration. However, more skeletal stability in conventional treatment was assessed. Both surgery-first approach and conventional treatment with presurgical orthodontics resulted in favorable skeletal changes in class-III malocclusion patients. Moreover, these findings should be discussed further due to the variety of study designs, outcomes and biases. Current evidence in this field still needs to be expanded. The authors wish to see more well-designed randomized controlled trials with long-term follow ups to confirm the results.

Laser Surgery of Soft Tissue in Orthodontics: Review of the Clinical Trials.

Introduction: Recently, a wide variety of procedures have been done by laser application in orthodontics. Apart from the mentioned range of various treatments, laser has become a tool for many soft tissue surgeries as an alternative to conventional scalpel-based technique during orthodontic treatments in the management of soft tissue. Due to scarce information in the latter subject, this study was designed in order to include clinical trials that included soft tissue ablation by laser in orthodontics. Methods: Literature was searched based on PubMed and Google Scholar databases in 5 years (2010-2015) with English language restriction and clinical trial design. Studies that performed soft tissue application of laser during orthodontic treatment were extracted by the authors. Results: Only eight studies met the inclusion criteria. No significant difference was found between laser ablation and conventional scalpel technique in the matter of treatment outcome. However, few issues remained to clarify the differences in the mentioned procedures. Conclusion: Laser performance can be recommended in case of preceding less bleeding and discomfort during surgical procedure. There are still quandaries among clinical application of scalpel-based surgery in aesthetic region with bracket-bonded teeth. Precaution and knowledge regarding the characteristics of laser beam such as wavelength, frequency, power and timing is extremely needed.

Analysis of Transforming Growth Factor- ß1 Expression in Resorptive Lacunae following Orthodontic Tooth Movement in An Animal Model.

OBJECTIVE: Root resorption is a complication of orthodontic treatment and till date, there is a dearth of information regarding this issue. The aim of this study was to determine whether the expression of transforming growth factor-ß1 (TGF-ß1, an inflammatory cytokine) is related to orthodontic force. Moreover, if associated, the expression level may be helpful in differential diagnosis, control and ultimate treatment of the disease. MATERIALS AND METHODS: In this experimental study, a total of 24 eight-week-old male Wistar rats were selected randomly. On day 0, an orthodontic appliance, which consisted of a closed coil spring, was ligated to the upper right first molar and incisor. The upper left first molar in these animals was not placed under orthodontic force, thus serving as the control group. On day 21, after anesthesia, the animals were sacrificed. The rats were then divided into two equal groups where the first group was subjected to histological evaluation and the second group to reverse transcriptase-polymerase chain reaction (RT-PCR). Orthodontic tooth movement was measured in both groups to determine the influence of the applied force. RESULTS: Statistical analysis of data showed a significant root resorption between the experimental group and control group (P<0.05), however, there was no significant difference in the expression level of the inflammatory cytokine, TGF-ß1. CONCLUSION: Based on the findings of this study, we suggest that there is a direct relationship between orthodontic force and orthodontic induced inflammatory root resorption. In addition, no relationship is likely to exist between root resorption and TGF-ß1 expression in the resorptive lacunae.

Effect of local injection of Zolena, zoledronic acid made in Iran, on orthodontic tooth movement and root and bone resorption in rats.

Background. Anchorage control is an essential part of orthodontic treatment planning, especially in adult patients who demand a more convenient treatment. Zoledronic acid (ZA) is an effective choice to address this problem. It is the most potent member of the bisphosphonates family that has an inhibitory effect on bone resorption by suppressing osteoclast function. Therefore, ZA might be a good option for orthodontic anchorage control. The current study evaluated the effect of local administration of Zolena (ZA made in Iran) on orthodontic tooth movement (OTM) and root and bone resorption. Methods. The experimental group consisted of 30 rats in 3 subgroups (n=10). Anesthesia was induced, and one closed NiTi coil spring was installed between the first molar and central incisor unilaterally, except for the negative control group. The positive control group received vestibular injection of 0.01 mL of saline next to the maxillary first molar, and 0.01 mL of the solution was injected at the same site in the ZA group. After 21 days, the rats were sacrificed and the distance between the first and second molars was measured with a leaf gauge. Histological analysis was conducted by a blind pathologist for the number of Howship's lacunae, blood vessels, osteoclast-like cells and root resorption lacunae. Data were analyzed with ANOVA, Tukey test and t-test. Results. There were no significant differences in OTM between the force-applied groups. ZA significantly inhibited bone/root resorption and angiogenesis compared to the positive control group. Conclusion. Zolena did not decrease OTM but significantly inhibited bone and root resorption. Zolena might be less potent than its foreign counterparts.

Ultraviolet-induced surface grafting of octafluoropentyl methacrylate on polyether ether ketone for inducing antibiofilm properties.

Since octafluoropentyl methacrylate is an antifouling polymer, surface modification of polyether ether ketone with octafluoropentyl methacrylate is a practical approach to obtaining anti-biofilm biocompatible devices. In the current study, the surface treatment of polyether ether ketone by the use of ultraviolet irradiation, so as to graft (octafluoropentyl methacrylate) polymer chains, was initially implemented and then investigated. The Fourier-transform infrared and nuclear magnetic resonance spectra corroborated the appearance of new signals associated with the fluoroacrylate group. Thermogravimetric curves indicated enhanced asymmetry in the polymer structure due to the introduction of the said new groups. Measuring the peak area in differential scanning calorimetry experiments also showed additional bond formation. Static water contact angle measurements indicated a change in wettability to the more hydrophobic surface. The polyether ether ketone-octafluoropentyl methacrylate surface greatly reduced the protein adsorption. This efficient method can modulate and tune the surface properties of polyether ether ketone according to specific applications.

Comparative effectiveness of Low Level Laser therapy and Transcutaneous Electric Nerve Stimulation on Temporomandibular Joint Disorders.

Introduction: Temporomandibular joint disorders (TMDs) are the most common source of pain on the face. There are multiple etiologies, and several types of treatment have been reported. The use of non-invasive and reversible therapies in the treatment of such problems is recommended. The present study evaluated the effect of low-level laser (LLL) therapy and transcutaneous electric nerve stimulation (TENS) on TMDs. Methods: In this single-blind study, 40 patients with temporomandibular disorders were randomly divided into four groups: TENS (TENSTem dental), LLL (diode 810 nm CW), shamTENS, and sham-LLL. All subjects were examined and data on pain and tenderness in the temporomandibular joint (TMJ) and masticatory muscles (using the visual analogue scale) and mouth-opening (distance between incisal edges before feeling pain; mm) were collected before baseline (T1), after each session (T2-T5) and one month after the end of the sessions (T6)), and analyzed using repeated measure analysis of variance (ANOVA) and Bonferroni statistical tests. A P value < 0.05 was considered significant. Results: The decrease in pain (P=0.000), tenderness (P=0.000) and increase in mouth-opening ability (P=0.002) was greater in the TENS and LLL groups than in the placebo groups. At the one-month follow-up, significant decrease in pain and tenderness was recorded in the TENS and LLL groups (P=0.000). There was no significant differences between TENS and LLL and the placebo groups for maximum mouth-opening at the end of the study (P=0.692). Conclusion: Using TENS or LLL therapy can improve TMD symptoms at least for the short term. Although the effects of the placebo played a role in improving symptoms, their effects were less important.

Evaluation of primary stability of innovated orthodontic miniscrew system (STS): An ex-vivo study.

BACKGROUND: Stability is determined as one of the requirements in use of Temporary Anchorage Devices (TAD) in orthodontics. Miniscrew has been a widely used Bone Anchor. Compared with mini-implant that necessitates osseointegration; mechanical retention is a determining factor for primary stability of miniscrew. Studies investigated various ways to increase primary stability. The aim of this study is to introduce a new configuration of miniscrew system which is believed to obtain more primary stability. MATERIAL AND METHODS: Freshly ovine mandibles were cut in blocks. Twenty-seven miniscrews (diameter 1.6 × 8 mm; G2, Dual Top Anchor System, Jeil Medical, Seoul, Korea) were inserted in the blocks and divided in 2 experimental groups: single miniscrew and the innovated design "Seifi Twin Screw (STS)". Primary stability was evaluated by Periotest "M"® device. RESULTS: Independent t-test showed a significant difference between 2 experimental groups in periotest evaluation (p< 0.05). STS demonstrated higher primary stability due to its mechanical configuration and design. CONCLUSIONS: The STS provides higher primary stability and was found to be effective in increased success rate of miniscrew systems from the standpoint of primary stability. KEY WORDS: Anchorage procedures, anchorage techniques, orthodontic anchorage procedures, miniscrews, temporary anchorage device.

The Effect of An Angiogenic Cytokine on Orthodontically Induced Inflammatory Root Resorption.

OBJECTIVE: Orthodontically induced inflammatory root resorption (OIIRR) is an undesirable sequel of tooth movement after sterile necrosis that takes place in periodontal ligament due to blockage of blood vessels following exertion of orthodontic force. This study sought to assess the effect of an angiogenic cytokine on OIIRR in rat model. MATERIALS AND METHODS: In this experimental animal study, 50 rats were randomly divided into 5 groups of 10 each: E10, E100 and E1000 receiving an injection of 10, 100 and 1000 ng of basic fibroblast growth factor (bFGF), respectively, positive control group (CP) receiving an orthodontic appliance and injection of phosphate buffered saline (PBS) and the negative control group (CN) receiving only the anesthetic agent. A nickel titanium coil spring was placed between the first molar and the incisor on the right side of maxilla. Twenty-one days later, the rats were sacrificed. Histopathological sections were made to assess the number and area of resorption lacunae, number of blood vessels, osteoclasts and Howship's lacunae. Data were statistically analyzed using ANOVA and Tukey's honest significant difference (HSD) test. RESULTS: Number of resorption lacunae and area of resorption lacunae in E1000 (0.97 ± 0.80 and 1. 27 ± 0.01×10(-3), respectively) were significantly lower than in CP (4.17 ± 0.90 and 2.77 ± 0.01×10-3, respectively, P=0.000). Number of blood vessels, osteoclasts and Howship's lacunae were significantly higher in E1000 compared to CP (P<0.05). CONCLUSION: Tooth movement as the outcome of bone remodeling is concomitant with the formation of sterile necrosis in the periodontal ligament following blocked blood supply. Thus, bFGF can significantly decrease the risk of root resorption by providing more oxygen and angiogenesis.

Evaluation of caries risk reduction following preventive programs in orthodontic patients, using Cariogram computer model: A quasi-experimental trial

ABSTRACT Objective: This study evaluated the effectiveness of preventive strategies on caries risk reduction in patients undergoing orthodontic treatment, using the Cariogram program. Methods: In this quasi-experimental study, samples were selected using a convenience quota sampling technique, in a public dental school. At first, caries risk profile was determined for each subject using the Cariogram before brackets bonding. The sample size consisted of 36 patients. The intervention group (n = 18) received preventive programs, and the control group (n = 18) was trained based on the routine oral health education by means of pamphlets. Then, Cariogram parameters were calculated for patients in both groups after six months. Results: The age range of participants was from 12 to 29 years. The mean percentage of the "Actual chance of avoiding new cavities" section in the intervention group increased from 45.72 ± 21.64 to 62.50 ± 17.64. However, the mean percentage of other parameters - such as "Diet", "Bacteria" and "Susceptibility" - decreased after six months (p< 0.001). Besides, the differences in the mean percentage between intervention and control group at the end of the study period (T1) related to the Cariogram parameters were statistically significant (p< 0.001). Accordingly, the mean percentage of 'Actual chance of avoiding new cavities'' parameter in the intervention group (62.50) was statistically higher than in the control group (42.44) (p< 0.001). Conclusion: Implementing different preventive approaches is able to reduce the caries risk in patients undergoing fixed orthodontic treatment, which can be clearly demonstrated using Cariogram program.

RESUMO Objetivo: O presente estudo usou o software Cariogram para avaliar a eficácia de estratégias preventivas para redução do risco de cáries em pacientes sob tratamento ortodôntico. Métodos: Nesse estudo quase-experimental, as amostras foram selecionadas por meio de uma técnica de amostragem por cota de conveniência, em uma faculdade pública de Odontologia. Inicialmente, o perfil de risco de cárie foi determinado para cada indivíduo usando o Cariogram antes da colagem dos braquetes. A amostra consistiu de 36 pacientes: o grupo experimental (n = 18) recebeu programas preventivos, e o grupo controle (n = 18) recebeu orientações sobre a saúde bucal por meio de folhetos. Após seis meses, os parâmetros obtidos por meio do Cariogram foram calculados novamente para os pacientes de ambos os grupos. Resultados: A faixa etária dos participantes foi de 12 a 29 anos. A porcentagem média da seção "Probabilidade real de prevenir novas cáries" no grupo experimental aumentou de 45,72 ± 21,64 para 62,50 ± 17,64. Por outro lado, a porcentagem média de outros parâmetros - como "Dieta", "Bactérias" e "Suscetibilidade" - diminuiu após seis meses (p< 0,001). Além disso, as diferenças nas porcentagens médias entre o grupo experimental e o grupo controle ao fim do estudo (T1), relacionadas aos parâmetros do Cariogram, foram estatisticamente significativas (p< 0,001). Assim, a porcentagem média do parâmetro "Probabilidade real de prevenir novas cáries" no grupo experimental (62,50) foi estatisticamente maior do que no grupo controle (42,44) (p< 0,001). Conclusão: A implementação de diferentes abordagens preventivas pode reduzir o risco de cárie em pacientes sob tratamento ortodôntico com aparelhos fixos, o que pode ser observado claramente por meio do software Cariogram.

Tooth movement alterations by different low level laser protocols: a literature review.

Low-Level Laser Therapy (LLLT) provides several benefits for patients receiving orthodontic treatment. According to some literatures, Orthodontic Tooth Movement (OTM) can be enhanced but some investigators have reported contradictory results. This article reviews the literature regarding the different aspects of the use of LLLT on OTM and its alterations. The general data regarding the study design, sample size, wavelength (nm), power (mW), and duration were extracted and recorded independently. Electronic databases of PubMed and ScienceDirect from January 2009 to August 2014 were searched. Also Google Scholar and grey literature was searched for relevant references. Some investigators found that the amount of tooth movement in the Low-Energy Laser Irradiation (LELI) group was significantly greater than in the nonirradiation group by the end of the experimental period. Low-level laser irradiation accelerates the bone remodeling process by stimulating osteoblastic and osteoclastic cell proliferation and function during orthodontic tooth movement. But some researchers have reported that no statistical differences in the mean rate of tooth movement were noted between low energy and high energy experimental sides and their controls. Some evidence shows that low-level laser irradiation accelerates the bone remodeling process and some evidence shows that LLLT has not effect on OTM. In some investigations no statistical differences in the mean rate of tooth movement can be seen between low energy and high energy experimental sides and their controls. It has been shown by authors that laser irradiation can reduce the amount of OTM and a clinical usage for the inhibitory role of low level laser irradiation is enforcing the anchorage unit.